Even if I set the terrain tag on a tileset to something like 2, and then put in 2 for NO_ENEMY_TAGS = [2], then change the map's tileset to a different tileset and then set it back to the original. The enemy still walks over. I tried it on a body of water and the enemy still walks all over it.
Don't even have to change the tileset to reproduce it. Doing a search for NO_ENEMY_TAGS in the scripts shows that it only appears in one method: get_respawn_coordinates. This has nothing to do with movement passibility, so either the User Manual typo'd or it's a regression.