If the AI hears a shot or a bullet hits a ground around the AI, it will start scanning the horizon for a possible threat, eventually also entering the combat behavior.

The closer the source the better direction estimate. So instead of scanning the horizon, the AI turns immediately to the source. It already knows that there's a possible threat from the audible information, so once it has a visual confirmation it can immediately open fire.

However the AI shouldn't be able to place a precise shot because at that point it's still penalized by distraction and the fast turn.

Could you please provide more detailed info? (ideally a repro mission where a clearly wrong behavior would reliably happen)

Thanks a lot!