Hi there and welcome. From a player, thank you for this report. I have been working to find the source of random thrall deaths, and this is a very good lead.
Also, I swim to my base many times daily, and my “spider sense” has been going off for a while now about my follower(s) drowning. Your report has helped me understand, although I’m playing on Exiled Map, there is a risk. I’m sorry for your loss, there’s no mechanism for getting back your killed thrall or its possessions. All you can get is our thanks.
