SdKfz251 MG42 targeting bug - crosshair shows no penetration

I have weird bug with SdKfz251's MG42. When I choose this halftrack and then want to give it order to attack enemy infantry, the crosshair (which shows up when you put your cursor on enemy unit) shows that it can't penetrate it (you know, it shows when you choose for example Grenadiers without any antitank weapon and put cursor on a tank - it is different animated red cross) - even though the target is infantry, which doesn't have armor. When I right-click the enemy infantry anyway, the 251 drives straight into enemy squad (when any other unit is ordered to attack the enemy, they stop right away at the furthest distance available and shoot at them), it shoots them but they drive around into enemy squad as if it was pursuing enemy model. I have to attack enemy units by ordering the halftrack to stand in front of enemy because of it, if I give direct attack order then this weird circus performance begins.

Anyone knows why it happens?

I checked halftrack's MG penetration - it's 1,3, 1,6 and 2,1 for far, mid and near distances, so it can't be simply because of pen set lower than 1.