OK, let me make sure we're not confusing issues here too. NV's water LOD is broken in vanilla and a separate issue from what I posted above which is Fallout 3's wasteland worldspace. The Fallout 3 worldspace is where the cells have individual water height which differs from the default height in the worldspace record.
There is no problem with water height. If cell water is defined it is used. Otherwise the worldspace LOD water height is used with fallback to water height.
I find that in FNV some worlds only have sky reflections and some reflect terrain and objects.
There is a difference in the terrain LOD nifs that changes the LOD water reflections to match the reflection of the loaded cell water. The two types of worldspaces need their correct types of terrain LOD nifs. Using the wrong type results in visual problems like the one you posted.
Based on the terrain NIFs, these worldspace only have sky reflections:
These worldspaces have decent reflections. I find they are more consistent and without the glaring bugs/omissions like Skyrim, Skryim SE or Fallout4:
Any other worldspaces not listed does not seem to have LOD water.
I would have assumed this is controlled by a worldspace setting or a the default image space reference, but I haven't figured yet how he game decides.
In any case, for now I can automatically control xLODGen terrain LOD output with the LOD options files.
Edited by sheson, 04 July 2018 - 09:51 AM.