I just found an additional buggy cave where you swim inside since patch 1.2.0.
Cave location: St. Kenhelm´s Fall in Glowecestrescire...
Same as the one cave next to Anlaf´s Lookout in Northumbria.
I´m not sure if this is the case for everybody, but I glitched into this bug via moving the mouse to the top view and see Eivor from the above...
So, hopefully someone from the Forum moderator will see it and report to the Devs.