WORLDEDIT-3604 - Reported by HeadlessJoey

I'm using Spigot 1.12.1 with the builds 6.1.7.3 and 6.1.9 but both have the same issue.
When I use //copy it's all fine but using //undo I get this big error and only a few blocks are undone or nothing at all: https://pastebin.com/zdj6UB88

Same issue with the //cut, nothing gets removed https://pastebin.com/Y4d2QGx8

Hope it's easy to fix, kind of stuck right now.

Comment by HeadlessJoey

Sorry forgot to add. It happens when I try and do it with one of those woodland mansions. I first thought it was cause of flowing water but that didn't change anything when I removed it.
Smaller selections seems to work but like I said, a woodland mansions gives me these errors.

Comment by HeadlessJoey

Ok after a lot of testing it was the wall banners in the mansion that broke it!
Not sure why but they seem to be the whole cause of the not being able to cut or undo.