Then ask your instance admin to update to 0.18.4. I don’t see this bug using the same Jerboa version on my home instance, which has already updated.

Yes, when you open the homepage of your instance in a browser and scroll to the bottom, it should say something like “BE: 0.18.4”.

If it says that and you still get this bug, it’s a new one.

Which Jerboa and Instance backend versions are you seeing this with? There was an issue in the backend that could produce this behavior but should be fixed in 0.18.4: https://github.com/LemmyNet/lemmy/pull/3823

Which front end would show both names? On (mobile and desktop) web and in Jerboa I only see the display name if it’s set. And the only limitation seems to be that a leading @ is not allowed.

Tbh I think the display names as they currently work are dangerous. What would prevent me from setting my display name to nutomic@lemmy.ml? Most front-ends would not show that I’m actually not you at first glance.

Edit: Misread the question as being about display names. Full unicode support for usernames would be even more dangerous, basically opening the door to unicode homograph spoofing on that level too.