Is there some special logic for the first post of the topic?
i can only find these 2 settings and they are for time ranges for edting, but there is a user reporting that edit is not available for his topic the user opened, so the first post. He can edit the other posts but not the first one O.o
He should be able to edit, maybe he reached the maximum number of edits for the day? check the max edits per day site setting.
If this is for a hosted site, you can send us a PM with the username of the user that’s having issues and a link to the specific topic, so we can investigate it further.