Sounds like a problem with Memmy. Does this link work? https://lemm.ee/c/sfah@hilariouschaos.com
You should be able to search communities in your app and could have searched “sfah@hilariouschaos.com” too.
But basically communities on Lemmy are in the form of “name@host”. The “name” can be whatever someone wants, and the “host” is the website / Lemmy instance where that community originates from. But because it is federated it’s all available everywhere (generally speaking). For example, if you visit https://lemmy.world/c/sfah@hilariouschaos.com it should be the same content just loaded via lemmy.world instead of lemme.ee. However if theoretically someone went and made a “sfah@lemmy.world” community, that would be a completely separate community from the above, hosted on a different Lemmy instance.
Another solution to this situation is to squash your changes in place so that your branch is just 1 commit, and then do the rebase against your master branch or equivalent.
Works great if you’re willing to lose the commit history on your branch, which obviously isn’t always the case.