I downloaded and ran your scenario.
For the first round I tried, I had the same experience.
From observer view if I switched to gunner view and did not touch anything, and then switched back to observer view the gunner would fire again. I had to do this each time to get the gunner to fire.
For the second round, I sat in the commander's view and noticed that after the first round was fired I needed to press the Battle Range button and the gunner would lase and fire again. I did not find targets for the gunner. I let him find targets, told him to fire, and waited. Nothing happened. As soon as I hit the Battle Range button, he would lase target and fire. I did not have to find a target or tell him to fire, or re-engage. All I had to do was press the Battle Range button after each fire. Sometimes I would Battle Range and Reset, if he didn't fire after only a Battle Range.
For the third round I sat in the commander's view and just pressed the Reset button after each firing of the gun, or whenever the gunner found a target. He would range the target and fire. HOWEVER, on the LRF panel whenever a 2 appeared in the red number box above the range value when the gunner lased a target he would not take the shot. I would reset and the range would go to zero and then he would fire without lasing again. If a 1 showed up after he lased he would fire on his own, but never on a 2.
For the 4th round I only switched in and out of the commander's view and after the first round was fired he would never reset the LRF, thus the gunner would never lase another target, and without a new lase would not fire. Whenever I switched from commander to gunner though, the LRF would be reset. I then would switch back to commander from gunner and I could see that the LRF was reset, (zero range and range light flashing) and then the gunner would lase and fire. To make this happen all I did was switch from commander to gunner and then back to commander without touching anything.
I am going to take a SWAG here and say that the commander is not resetting the LRF between shots, and that the gunner does not like a 2 in the other box. I am going to assume that the single digit box, with the 2 in it, is the number of returns from the lase, but not sure. But if it comes up 2 instead of 1 that AI gunner is not firing until the LRF is reset again.
I cannot sit in both positions gunner and commander at the same time or just observe the AIs, so switching between the two is indeterminate.
Cool scenario though. Once I just sat in the commander's seat and just pressed LRF Reset button after each round was fired and we killed all of the enemy targets.