Terrain positioned incorrectly and appears to vibrate in far-out cells
At 0,0 and in nearby exterior cells the terrain looks and behaves exactly as it does in vanilla Morrowind, fixed compared to the position of the statics and water. However, as you go further out from origo, they disconnect, no longer moving in unison. In Sheogorad, the terrain appears to vibrate as you walk, compared to the statics and the water. (The statics and water appear to have the same relative position.) This the easiest to see where statics are close to a 180 degree angle with the terrain.
If you install a mod that further extends the landmass (such as Tamriel Rebuilt) the problem is even more noticable. At Bosmora (33,-30) the vibrations have transformed into a full-on earthquake, and certain rocks appear to be floating in the air (Though it mostly looks fine if you stand still).
This happens to me in OpenMW 0.30 on Windows and Linux (Haven't tested anything else). You should be able to notice it if you go to the locations shown in the screenshots and the video linked below.
https://imgur.com/a/nATQc http://youtu.be/paf4Qaz8p7M
(RM-1563 from redmine: created on 2014-06-26 by Isak L, , closed on 2015-11-08 by nobody, relates #2005 (closed), duplicates #757 (closed))