"The Swimmer" moves away after leading you to underwater cave

In the Bloodmoon quest "The Ritual of Water" a black horker called "The Swimmer" (bm_horker_swim_unique) leads you to the location of an underwater cave. In vanilla Morrowind he keeps floating above the location of the cave, while in OpenMW he will start moving away again, towards the southwest as long as you stay with him.

Steps to reproduce:

1. Journal BM_Water 10
2. coe -27, 24
3. Follow the black horker on the island

OR use provided savegames, follow the Swimmer the last few meters and observe

OpenMW version: 0.36.1

(RM-2697 from redmine: created on 2015-06-17 by Thomas Staudinger, , closed on 2015-12-07 by scrawl ., relates #3080 (closed))

Attachments: The_Swimmer_2.7z TheSwimm0000.7z