She considered leaving the band after that Australian incident. Then Covid struck, and Chvrches ended up making a fourth album, 2021's Screen Violence, remotely.
She finally took the plunge a year later, but not before signing a new record deal with her bandmates, assuring the future of the project.
"I was conscious it would give people a sense of security, that I’d made a commitment," she says.
"I don’t know that that’s how it actually works, but that was my hope."
She’s keen to stress there’s no bad blood: Doherty and Cook have given her their full support. Still, it’s natural for someone leaving a band to define themselves in opposition to that music - otherwise what’s the point?
As Mayberry succinctly puts it: “I didn’t want to make a crap knock-off Chvrches record.”
In recording sessions, she'd flinch when anyone pulled out a vintage synth. Instead, she pursued a more organic, lyrics-first approach.
But after a decade in a trio, the instinct to compromise was hard-wired.
“I'm very used to arguing my point, then trying to see other people's point of view," she says.
"So it was a real learning curve to be like, ‘No, this is my opinion, and if I don't think it's right, then it's not right, and that's the end of the conversation'.”