Going to tentatively mark this as fixed, I did some jiggerypokery with my zfs backups so they don't share pool names.
I think this exposes how fragile the exclusive access system is though, and there should probably be a way to force it on, especially now that you can have lots of tiny little purpose built pools. I don't want to worry that one of them might have a folder that shares a name with an unraid share, both for performance reasons and because suddenly having FUSE start smudging files together is a bug factory
