[Mobhack]

It is not a bug.

Penetration (including any special hits) is determined first.

Then any bounces are diced for. So it can still ping off.

Then defending armour is determined including defending armour increases due to horizontal angle off, area of hit etc, track hits, HEAT fuse failures and so on.

Then overpenteration is determined (HE will need signifigant overpen to have an effect on armour).

There is rather a lot more than simply pen >= armour.

Cheers
Andy