I've had this bug a few times now, but it's hard to reproduce and didn't manage to record it yet.
So I'll just describe what happened.

I was doing cargo on a server where I also admin on. To check something out, I enabled /vanish on cargo (I wasn't mounted or anything), checked something, came back to cargo, used /vanish again and continued with the cargo take.

Tens of minutes later we left cargo on a minicopter, but on arrival when getting off from the mini, I was at high speed dragged in/under the map to a seemingly random point; but relatively close to where I vanished earlier. The game then killed me and kicked me for InsideTerrain Violation Level 200.

Upon coming back using Vanish + AdminRadar I managed to find my body, floating in the water under the map.

Feel free to ask any questions, and if someone else has had a similar experience, please also respond. I've had this happen three times now in the past half year or so.

Ok I’ll look into this some how when you left cargo you stayed parented so when you got off the mini your body moved with the cargo ship presumably as it was moving out of the map. 

Yea seems like it. I died and got kicked before I got even close, but that's because the anti-cheat acted quickly.