[2019] Singleplayer T4 thrall missing

Hey @MarkSawyer

Welcome to our community and don’t worry about your English, it’s good
Regarding the wanderers, since the way single player and online servers work is different, it is possible that in your single player game they have gone to somewhere far from their initial path. On official servers, they are reset every time the server restarts, so if they get stranded they will always fall back to their original spawn. On single player, that is not happening.
We would recommend leaving the area and exploring other places, then coming back to the river again and see if they spawn again.