If you build the heavy orbital bombardment upgrade on the ACU, and then transport the ACU somewhere it stops working and will not fire missiles.
Deleting the upgrade and rebuilding it makes it functional again.
This does not affect the light orbital bombardment. It continues to function after transporting.
If you build the heavy orbital bombardment upgrade on the ACU, and then transport the ACU somewhere it stops working and will not fire missiles. Deleting the upgrade and rebuilding it makes it functional again. This does not affect the light orbital bombardment. It continues to function after transporting.