Not sure if this is a bug or not.
If a user tray to edit a page without cookies, the edit is not accepted.
There is no error message after or information before the edit, the edit simply has silently no effect. Same with login, no cookie no login, but no message why. If this is so in general with dokuwiki, this is not a good behavior.
It needs a check if cookies are active? Or it is a side effect of options?
If this is part of security check, is could be partially saved by using the IP instead of the session ID, if cookies are not activated. This is not perfect if the user has a fast changing IP, but it is better then nothing.