I'm getting this same issue on Syria at present. Any target with a building as backdrop is effectively invisible to Petrovitch.
nullIt's admittedly crude but I include an image of the target area of a (botched) attack run here, from the rough direction of the attack run. Targets on the road or in more open spaces (green)were easily acquired and engaged by Petro. Ones which had buildings behind them, even if not particularly close (in red, that BMP-1 on the right strikes me as a particularly bad example) were not targetable, even at very close range.
Somewhat disappointingly, I tried to reproduce this to generate a short .trk - but was unable to. I've had this happen twice over the course of this week in multiplayer, but it works fine in singleplayer, apparently.
I don't know if any of that is helpful, but I really hope so, it's been a bit of a drag.