I think this ticket is not a good fit to be assigned.
No experience with LDPA. Not used to working on identity flows and related stuff either.
Maybe someone else can review it?

Having said that, please find some analysis below.

Analysis

I suppose that to start with, when creating the user in Lime (during auto-creation) it should be done in lowercase. And then, when logging in and setting the “identity”, it should be done in lowercase as well.

The problem with that is that if someone usually uses uppercase, and already has a user in Lime with uppercase, it could become a problem.

To avoid that happening, you should create the user in lowercase, and in login look for one that matches exactly or, if it doesn't match, try with lowercase. But it doesn't seem like a good idea to let it work like that.