Penetration Bug?

[Djuice]

Is this a bug, i consistantly get a msg saying "You have hit a weak spot and increased penetration of **" Or something like that, but then afterwards it says that it was a non-penetrating hit, and therefore does nothing. This happens alot with HEAT and HE type weapons. Even tho the weaken penetration figure is already enough to penetrate the so called target. This also seems to happens mostly against Wheel/Tracked APCs, and MBTs. Whats with that?