I have a beam unit, the Cybran T4 Stun Cannon, in AI Wave Survival mod that keeps firing over the tops of units. I've tried a lot of different trial and error fixes, but with no luck (removing different flags, completely changing weapon, etc).
The beam always passes over the tops of units. I tried changing the weapon to a projectile instead of a beam, and then it began firing short of the unit. So beams = shoot over the unit. Projectile = shoot the ground short of the unit (as though aiming at something underground, shoots short regardless of direction unit is moving).
The Stun Cannon also has an alternate weapon that is shorter range, that is a projectile. This weapon fires without a problem.
I did see someone posting about a similar bug with a weapon from a different mod, where the weapon fired over the tops of units.
https://forum.faforever.com/topic/362/wyvern-battle-pack-v5-for-all-game-versions/10?_=1694449251893