September 26th, 2015, 16:59
As someone who's endured many hours of tweaking, deleting and re-installing, as mentioned before, the crew at Fullterrrain.com are magnificent, as are the chaps here. But I recently had a very similar event, though mine were the plateaus on many airports and trees in the water. It came down to, I believe, installing too much at the same time and not giving FSX a chance to integrate all successfully. I went through and reinstalled Global base and Global Vector and it seemed to fix the tree's in the water.
Here's some stuff that really helped me: http://www.orbxsystems.com/forum/topic/79004-resolving-rapid-ground-texture-morphing/