As I face this problem a second time, I have to report it here.
So basically “save wipe” does nothing. Server logs all players off and is unavailable for a couple of minutes but afterwards nothing has changed and every single asset is still as we left it.
In order to get a wipe done, the admins have to DELETE all spawned prefabs from a chunk by hand and wipe the chunk by hand. If you’re lucky and all chunks are wiped, the server wipe will finally go smoothly.
Try to wipe EU2