I resorted to resetting the bbPress data to nil, uninstalling and reinstalling the plugin, and the functionality is now working as expected. I’m not bothered about losing the forum content as there wasn’t much there anyway. I had one other issue with bbPress which seems to be due to a seemingly unrelated plugin. I’ve deactivated that plugin and filed a report with the developer. bbPress is now working like it should.
I’ve run the repair tool with the recommended option, and resaved the permalinks. No change – both the edit and merge links go to a ‘page not found’ error. Both are going through the [topic slug]/edit/ path – [topic slug]/edit/?action=merge for the merge link.
Something else I’ve tries is to create a dummy account at the moderator level, and attempted editing and merging topics. Same issue, both at the moderator and keymaster levels. Same problem with the edit link on replies too.
If it would help any, I can provide a link to the forum in question.