some more additional information (since I can’t sleep anyway)
I added more plugins to the second installation (the fresh one) and there everything works fine…
Then I tried more stuff on the real instance.
I deactivated all plugins –> permalinks are still not changable.
So I then tried out what happens if I play around on the database. (of the real wordpress instance not the second (new) one!)
So there was a page with the title “lorem” and a permalink “ipsum”.
I change the value of the field ‘page name’ to ‘lorem’ the permalinks updated to ‘lorem’. So that works.
If I delete the value of the field I can then set it via wordpress interface just fine (but just once, then its locked again)
So I think this might not be a problem with .httaccess but with the database?! or a plugin preventing the change to be written to the database.
( I get no error but also no confirmation if I press the “save” button near the permalink)
If this would be my personal site I would be fine by just changing the names of the fields in the database. But since its not my site and the pages will probably be renamed a few times till they settled for a title I would be quite fond if there is a solution to this problem.
Is there a log somewhere I could check?