Kicked by ghost admin then roll back to old save?

So me and my friends play on a 1.18.1 server, the world we play on is a map from what we can guess is 2012, around 1.2-1.3, so very old. At random intervals every single one of us, including the admin/owner will be kicked with the message "kicked by an operator" then the server will rollback and erase a couple hours of progress. We originally thought it might have to do with backups and so we tried disabling them and doing manual saving, which did nothing, the owner is not very tech savvy and doesn't have any other ideas as to why this happens other than it maybe have to do with the map download being so old.