Updated to 28.02. Was hoping it would fix this issue which has happened since my update to 28. Sadly, it did not and my log is filled with tons of these error messages:
InvalidParameterException Parameter “guestName” for route “core.GuestAvatar.getAvatar” must match “[^/]++” (“Clemens/MH, Dave” given) to generate a corresponding URL.
I removed my guest users and added avatars to my 2 users and it did not solve the issue.