I believe they did something like force cloud-login with some software update a few years back.
They also apparently were downplaying a major security incident, and sued Brian Krebs for reporting on it: https://arstechnica.com/tech-policy/2022/03/ubiquiti-sues-jo....
I have some Ubiquiti stuff, and it works fine, but I've been meaning to look deeper into all this, but I just haven't had the time. I just stopped updating the controller software (none of their gear is external-facing, and IIRC it's only needed for configuration/management) because cloud login is an absolute dealbreaker for me.