We are 5 people playing on a very small server (with no mods) I host.
Today a very weird bug appeared. One of us started to receive damages from nowhere (no hunger, no poisoning) during day, with visual distortions as in a temporal storm, but he was the only affected.
Soon after a lot of drifter started to pop from nowhere, including many tainted and corrupt drifters, on surface. At some time not far from 6 corrupt drifters were on and in our base. It was full day.
We tried to restart the server, all the drifters immediately disappeared. But later it started again.
When my "corrupted" friend disconnects everything get back to normal (after we kill the remaining drifters). But every time he reconnects, it starts again.
At some point he choose to stop playing for the day. But soon after the same thing started to happen to another player.
I tried to fully deactivate mob hostility with /worldconfig creatureHostility off and temporal stability mechanic with /worldconfig temporalStability false, without success. Drifters kept attacking us.
I really don't understand what can cause this issue.
Thank you in advance.