As ones who knew EO of old, The maps were pretty much all created in the map program, Now Re-rendering it on new engine, You find silly flaws what they would of never noticed as it would of looked right.
Map 81 - CastleFall
Some of the floor bits are actually on layer2 which is pretty much your trees,signs etc. So the game was trying to show the grass floor, and stonefloor on top of each other,