Role removed while editing own account

I don't quite understand what you're saying.

Please describe with concrete names for users/roles/permissions
-- what you're doing,
-- what you're expecting to happen, and
-- what happens instead.

I have the same issue. But I think it's easier to repro this way:

- The user has the right to assign roles.
- Assign a role to an user which is not in the list of assignable roles.

Go to edit user page, this is shown:
"The user receives the combined permissions of all roles selected here and the following roles: Authentifizierter Benutzer, action_Verwalter."

Then Just hit save.
Afterwards action_Verwalter is removed from the assigned roles for this user (in fact, my self. I have to use another admin user to grant this role to me again)

I understand now what you're reporting, thank you.

This is a duplicate of #1954332: Problems with "sticky roles" static cache, which seems to be, unfortunately, a never-ending story...

Please follow up in that other thread.