Yup, that sounds like the same Living Settlements bug thaty is causing many players to lose their thralls. Funcom has been told (and should keep being told over and over again), and has acknowledged that they know it is happening and they are trying to find a solution. For some reason they refuse to turn off Living Settlements on official servers in the meantime, even though that would be a simple remedy (and is something they have done previously). Basically they have said they ‘don’t want to’, with no real explanation for why not.
If you’d like to add your vote and your opinion to the unofficial petition to get Living Settlements turned off on official servers until it is actually fixed and no longer killing thralls, you can find it here. Maybe if enough people speak up Funcom will stop focusing on Dune long enough to do the simplest thing they could (and should) have easily done months ago to prevent this problem.