How quaint it feels now to look back on the sort of low-level furore with which JK Rowling once had to contend. In 2009, Matt Latimer, a former speech writer for George W Bush, claimed in his book Speech-less: Tales of a White House Survivor that the Harry Potter creator had been dropped from consideration for the presidential medal of freedom because of suspicions in the administration that her books “encouraged witchcraft”. What the Wizarding World wouldn’t give today for a controversy of that stripe: one that doesn’t result in lost revenue, accusations of hate speech, and the previously unimaginable spectacle of Vladimir Putin declaring that he knows how Rowling feels.

It is in this volatile climate that Fantastic Beasts: The Secrets of Dumbledore, the third in the Harry Potter spin-off series, is being released. The movie begins with the dark wizard Gellert Grindelwald (played by Mads Mikkelsen) slinking into a tearoom, his nose twitching. “Can you smell it?” he hisses. “The stench?” He is referring to the aroma of the muggles – non-magic folk, that is – seated all around him, but anyone who has been paying attention to the fortunes of the once-invulnerable Wizarding World would be forgiven for reading the line as a commentary on the franchise itself.

Rather like the fantastic beasts catalogued by the magizoologist Newt Scamander (Eddie Redmayne), the problems facing the series come in assorted shapes and sizes. One of its stars, Johnny Depp, who played Grindelwald at the end of the first Fantastic Beasts film and throughout the second, was asked to leave by Warner Bros after losing his libel case against the Sun newspaper, which had referred to him as a “wife-beater” following accusations of domestic violence made against him by his ex-wife Amber Heard. Two years ago, another of the film’s stars, Ezra Miller, was videoed grabbing a woman by the throat in a bar in Reykjavik. Last week, the actor was arrested for disorderly conduct in a Hawaii karaoke bar; reports from the same night allege that Miller burst into a private residence and threatened the couple living there.

This all occurred alongside the controversy that has swirled around Rowling over the past few years, ever since a long essay she wrote about her gender-critical feminism put her at the centre of the row about trans rights. The world of Harry Potter and its Fantastic Beasts spin-offs has undoubtedly been marred by this. The question now is whether the damage is irrevocable, and even severe enough to kill off future projects. Anna Smith, a film critic and host of the podcast Girls on Film, concedes that the franchise has taken a few knocks. “The fact that both these things have happened to people involved in Fantastic Beasts has cast a bit of a pall over the series for some audiences,” she says. “I’m not sure they will prove catastrophic, however. There are probably enough people keen on the series who don’t know, or care, what Film Twitter is saying.”

The novelist Joanna Nadin, who has written more than 90 books for children and adults including the bestselling Worst Class in the World series, believes the significance of Rowling’s comments is far more wide-reaching than that. “It isn’t just Film Twitter or even YA Twitter,” she says. “These conversations go on among young people whenever the books or films are mentioned. She has tarnished her own brand as far as huge numbers of them are concerned.”

For evidence, check out the online response to Emma Watson’s appearance on stage at last month’s Bafta ceremony, where the actor amplified her previously stated message of support for the trans community by telling an appreciative audience: “I’m here for all of the witches.”

“The reason Emma Watson’s Bafta comment went viral is because this isn’t a limited issue,” says Nadin. “This is something millions of people are invested in. The young people I’ve worked with in the last five years, many of whom are trans, feel betrayed by someone who was a guiding light to them, who gave them a place to feel safe, where ‘difference’ was celebrated. Now we don’t use Rowling’s name or work in the classroom.”

Even before its current travails, there was a rinky-dink quality to the Fantastic Beasts franchise. From one angle, the idea of announcing a five-film cycle at the get-go felt like a mark of hubris (if we’re being grand about it) or an act of cynical exploitation (if we’re not). Rowling published the Harry Potter spin-off book Fantastic Beasts and Where to Find Them in 2001 to raise money for Comic Relief. Once the initial film, for which she received her first solo screenwriting credit, reached cinemas, it was not altogether clear that there was enough material for a single movie, let alone the other four that she had promised (or threatened, depending on your point of view). Extrapolating a threadbare story from what was originally a slim encyclopaedia of outlandish creatures had resulted in something very close to a two-hour game of Pokémon Go.

Released in 2016, the Fantastic Beasts and Where to Find Them movie contained pluses – including fine, intense work from Samantha Morton as an anti-magic preacher and Miller as her troubled son, Credence – but one distinct minus was Redmayne, whose mannered, ingratiating performance made Tom Hanks as Forrest Gump look like a study in Bressonian realism. Eyes darting diffidently, mouth semi-agape in a love-me pout, he seemed to be channelling Michael Crawford in Some Mothers Do ’Ave ’Em.

The reviews were generally kind, though, with audiences even kinder: the film grossed $814m worldwide (on a budget of $180m). But by the time the second movie, subtitled The Crimes of Grindelwald, rolled around two years later, the tenor had changed. The trade paper Variety declared that “real magic is in short supply”; the Telegraph diagnosed “one of the gravest cases of prequel-itis since Star Wars: The Phantom Menace”; and the Financial Times dismissed the picture as “a fatigued special effects show”, advising the film-makers to “abort any thought of Fantastic Beasts 3”. The budget for the second movie had risen to $200m but the international box-office was down to $654m. Not yet calamitous, perhaps, but cause for concern – and a sign that the Harrymoon was over. And the pre-release box office estimates suggest that Dumbledore will take at less than half of Grindelwald.

What has changed in the interim? Moviegoers have certainly started to react more strongly to the suspicion that they’re being sold a pup, as proved by the audience exodus from the Divergent franchise (the third episode, Allegiant, tanked so badly that a proposed fourth was scrapped), as well as the decline in enthusiasm for the rebooted Terminator series, where the subtitle of the final one – Dark Fate – said it all.

Could it be that the days of flogging a dead franchise are numbered, now that audiences not only have so many other viewing options, but such an array of platforms on which to make their displeasure felt? Disney’s approach to Star Wars illustrated that no movie cycle is too big to fail. The studio came a cropper in 2018 with Solo: A Star Wars Story, which became, as Vanity Fair put it at the time, “officially the first Star Wars movie to flop”. Two years later, the Disney CEO, Bob Iger, shouldered responsibility. “I think the mistake that I made – I take the blame – was a little too much, too fast,” he told the Hollywood Reporter, before confirming that “you can expect some slowdown”.

The most deleterious effect on the Wizarding World has been caused not so much by lacklustre product – Fantastic Beasts still has fans in abundance – but by Rowling herself. Warner Bros appeared to acknowledge as much when it issued a Secrets of Dumbledore trailer last year in which her name was invisible to the naked eye. Previous trailers had put the novelist front and centre; the first Fantastic Beasts trailer included a title card dominated by her name (“JK Rowling invites you”) while The Crimes of Grindelwald featured one announcing the new film “from writer JK Rowling”. When it came time to whet appetites for the third episode, she had become the dirty secret in The Secrets of Dumbledore, relegated to the small print at the bottom of the screen.

That move seemed consistent with last year’s reunion special, Harry Potter 20th Anniversary: Return to Hogwarts, which included no new interview footage from Rowling. Screen time went instead to the stars of the original franchise: Daniel Radcliffe, Emma Watson and Rupert Grint, all of whom had already distanced themselves publicly from Rowling, and declared their solidarity with the trans community. Redmayne, too, was vocal in his opposition to her views. “I disagree with Jo’s comments,” he said in 2020. “Trans women are women, trans men are men, and non-binary identities are valid.”

When you’ve got the stars of your own franchise lining up to contradict you, and Putin trying to align himself with your travails at the height of his hostilities against Ukraine (he compared the west’s attempts to “cancel” Russia, as he put it, with the treatment of Rowling by “fans of so-called gender freedoms”) then some kind of cosmic recalibration must surely be in order. Even those who remain entirely sympathetic to Rowling can’t fail to acknowledge that it is she who is preventing the smooth continuation of the Wizarding World. To use horror movie parlance, the call is coming from inside the house.

Regardless of the Rowling controversy, The Secrets of Dumbledore looks unlikely to bring about any miraculous upswing in the franchise’s standing. Common criticisms that the second movie was all world-building and no characterisation, or that Rowling had cluttered up the first two films with obfuscatory detail, seemed to hit home: for this third one, Steve Kloves, who scripted the entire Harry Potter series, is credited as co-writer. A steadier hand on the tiller would be hard to find, though it hasn’t resulted in an improved viewing experience. The new film feels simultaneously leaden and inconsequential, lacking the depth, clarity or calibre of ideas to justify a two-and-a-half-hour screen time.

The good news for Warner Bros is that the Harry Potter brand, distinct from Fantastic Beasts, appears insulated from retroactive harm. Interest in the original property shows no sign of waning, even among those fans who have abandoned their allegiance to Rowling. The stage hit Harry Potter and the Cursed Child continues to dominate Broadway and the West End, while last summer’s reunion documentary went down a storm on HBO Max, where a live-action Harry Potter spin-off series is in the early planning stages. “It’s interesting to see the generation who grew up with the books and films ‘owning’ them now,” says Nadin. “They’re able to say: ‘These belong to us, not her’ and remove her from the picture, which is, I think, a healthy attitude.”

But while Harry Potter seems ringfenced by the goodwill of loyal fans, the future of Fantastic Beasts is less certain. David Yates, who has directed every Wizarding World movie since Harry Potter and the Order of the Phoenix in 2007, confirmed recently that Rowling hasn’t yet started work on the fourth script in the series. Holding fire on that first draft until the takings are in for The Secrets of Dumbledore seems prudent. Unless any graduates of Hogwarts know of a spell suitable for laundering a sullied film franchise, this is a beast that may yet be put out of its misery.

• This article was amended on 8 April 2022 to rephrase a sentence that inadvertently appeared to downplay the actions of Depp and Miller, and to remove a description of a person that was not relevant to the story.

• Fantastic Beasts: The Secrets of Dumbledore is released on 7 April in Australia, 8 April in the UK, and 15 April in the US.