[Bug]: Cannot attack ground where terrain and water are the exact same elevation

### Describe the Bug

T3 Bombers (cybran ones confirmed) seem to completely ignore attack ground orders. It clears them as if they're invalid or unable to be navigated to.

### Reproduce the bug

Build a t3 strat bombers. Give it a ground target to attack (say in between some mexes). It will ignore or autoclear the order after a few ticks. If you give it waypoints first, watch as it flies to the nearest waypoint, clears the order, and effs off. Seems it won't drop a payload without an actual proper enemy target.

### Screenshots

On replay 27169021 the strat bomber at 13 minutes in is given a waypoint and an attack ground target. It gets to the waypoint, discards the attack ground order and starts doing it's own thing. Giving it attack ground orders directly never get issued or show up in the replay, so you can watch as I give it a waypoint that then just "disappears" because I tried to override it with an attack ground order.

### Additional context

_No response_