Just a few odd ones floated about, but there was never armies of them like this.
I think the update " * Disabled tavern visitors teleporting when no path is available" did this. If they spawn in water, that is considered to be “no path”, since NPCs don’t know how to swim, and just stay there drowning.
Visitors are also spawning on random flat surfaces like ontop of my Vault and floverpots and just stare at my tavern from there longingly
Can confirm on PS5. I found two underneath my base on siptah yesterday. I build port villages, so my bases are typically over water and use fence foundations for support. I popped off a ceiling tile on the floor and saw two there swimming in place in the water. I’m familiar with the sound as my thralls use to do this a lot when thralls would drop through the ground before. That’s why I checked.
I have the same bug periodically, playing solo on xbox. I saw this prior to the updates and it went away when I turned off Living Settlements. After turning Living Settlements back on, the bug returned. Probably realated to how Living Settlements interacts with the Tavern System, though that is just a guess on my part.
I’ve experienced this as well on PC, unmodded, with Living Settlements enabled. Not underwater as I don’t have bodies of water nearby, but my tavern patrons will consistently spawn in odd, inaccessible places e.g. below cliffs, on unconnected cliffs, or inside the terrain models.
Previously, I would sometimes find patrons at these locations, but they would teleport up to the tavern as soon as I traveled to it. After the March 25th patch, which removed this teleporting, the patrons are predictably stranded.