This bug is related to registration.
On the <Dokuwiki/doku.php/start?do=admin&page=usermanager> page, I click on a user to change his access rights.
I fill the "groups" filed of the "Edit user" panel with the following string: "Profs, Docs, Cours", where all three are valid group names.
Note that there are spaces after the comma.
Then I click on "Save changes". Everything goes fine, but the user cannot access any of the pages with a protected access for the members of those groups.
If I redo the same thing, this time without spaces "Profs,Docs,Cours", then it works!
Observe that the list of a user's groups is displayed on the "User List" panel with spaces "Profs, Docs, Cours": this is rather misleading!
Well, nothing very important, but it may waste some time to beginning users.