I've tried from my phone and my tablet. I've updated then uninstalled and reinstalled the game. Nothing is correcting this issue. I no longer get a menu when trying to edit the wall. It will pin or unpin an item but I can't edit or remove items.
What rank are you in your guild?
There should be what I believe is a gear shaped thingie on the far right of where your type is. If it's not showing up, go to the left of the page where the tab says guild wall. Be in that setting, then click again on the guild wall tab to expand it out further. U may find the gear then to do editing and removal.
Also u can't edit posts created by others but u should be able to delete. I'm guessing op is right and its a bug though
I think its something to do with rank, i seem to recall that the first rank able to post on wall, cant delete. I think that rank is officer. Not too sure, but if op is a champion or something then yeah, definitely a bug
I think the only option is to close up shop and start a new guild. Scorched earth and all that jazz.