This error kind of renders an AI weaker than it should be on certain maps.

I make maps that are a combination of land and water, and it's a bit annoying to see half of the enemy team helplessly stuck at the bottom of a river because the AI built them over water.

Another error that happens is that AI flyer units that have magnets will sometimes pick up non-amphibious units and drop them over water.

If the main computer on a unit is set to "never navigate on water". I don't understand why the AI would put that unit in the water regardless.