In game on 1.6.5 a visual bug results in occasional failures to render a node, exposing the sea level system below ground as per this screen shot:
Just swivelling the camera restores correct rendering as per the next screenshot:
This bug is disconcerting and immersion breaking. Each time there is a clean straight edge break in rendering at node boundaries as illustrated by this second screenshot:
Again, swivelling the camera restores correct rendering as per the next screenshot:
If this bug is limited to modded Main_map's it may relate to the absence of editor tools to create modded compressed shader caches - https://forums.taleworlds.com/index.php?threads/worldmap-compressed_shader_cache.445300/post-9725807 - or it may be unrelated.