1. Immich hosts user content on their domain. And should thus be on the public suffic list.
2. When users host an open source self hosted project like immich, jellyfin, etc. on their own domain it gets flagged as phishing because it looks an awful lot like the publicly hosted version, but it's on a different domain, and possibly a domain that might look suspicious to someone unfamiliar with the project, because it includes the name of the software in the domain. Something like immich.example.com.
The first one is fairly straightforward to deal with, if you know about the public suffix list. I don't know of a good solution for the second though.
I was just deploying your_spotify and gave it your-spotify.<my services domain> and there was a warning in the logs that talked about thud, linking the issue: