Its looking like this may be fixed. Here is a recent chat from micahmo in the thunder general chat on matrix

I Just noticed that this was posted by the snowe, the admin of programming.dev, which is the instance I use haha! Just thought it was cool that he used Thunder!

I read through that thread, and regardless of whether there's a limit or not, or there's an issue with the backend, etc., etc., I think it makes sense to remove the limit in Thunder. Specifically, snowe said this:

I can log in on every other app perfectly fine

If we were facilitating account creation, then sure maybe we should do a little more validation. But for login, I say let the user type whatever they want and let the backend handle it.

I'll open a quick PR to remove this limit. Of course, up to Hamlet, if you agree. 😊