[Bug Report] Invulnerable enemy?

[ShamrockOneFive]

Description: Flying a Career mission tonight, I was flying a Yak-1B on an intercept mission against enemy fighters and bombers attacking a friendly position. I engaged a FW190A-5 near the target area that appeared to be invulnerable. The first few shots on target I thought maybe I had not hit something important so I closed the range more and I gave this FW190 my entire ammo load with zero effect. No visual appearance of any damage and no apparent effect to the enemy at all. I should note that my aim was extremely good on this target and I probably hit with 80% or more (especially after I closed the distance).

Repeatable: Never seen this before.

Other Notes: I was recording a track file at the time so I can show this happening.