Have now had two name-tagged Toretoises disappear from their enclosure. The first one stuck around for quite a long while without incident; the other disappeared after less than a day. Both were in the same enclosure, which is a simple set of fences just big enough for them to fit into. They were both being repeatedly harvested by an Iron Rod on a sticky piston with a 10 second Hovering Hourglass, and being fed from my tiny automated Cave Root farm.

EDIT: Almost immediately after posting this with the original title, I saw the growth particles and then saw my Iron Rods cause some Coal to drop. So he's actually still there, just completely invisible. Leaving the original post contents for the other info it has.

I think both times happened after the server was restarted, but I can't swear to that.

Please let me know what additional info I can provide, if any.

EDIT2: My wife can see and interact with the Toretoises just fine. To my client, they are not only invisible but literally non-existent. I can stand in the middle of them, mine through them, etc. Re-logging while near them does bring them back; otherwise, their non-existence persists through reboots of the client and server.

Going to need a log for this.

Haven't had the issue appear again. Closing this.