It’s true that rebooting doesn’t usually fix the problem, and it’s also true that sometimes you have to get in touch with SmartThings support.
But it’s also true that because SmartThings allows you to assign a network ID through the IDE you can sometimes get rid of these ghosts on your own by following the method described in post 13 of the community error message FAQ that @bobbles linked to upthread.
I did a zwave repair a few days ago which finished with no errors.
I added 1 zwave device yesterday and ran the zwave repair this morning and it came up with 3 errors to device id’s that are not in my devices. I have no idea what they are based on the numbers.
I understand that they could be devices that were supposedly removed, but why would they show up all the sudden when nothing came up yesterday? I haven’t removed anything in quite awhile.