Had one incident with a Sherman that just would not die (or be tracked, or take damage) to cannon fire from many planes... IL-2's Huri-D's and such. Film was sent in in case there was a problem with the damage model. If you notice things like that in a new addition, or after a revision to the game, film it and send it in with what ever details you can provide (not suspicions, not accusations, ....details).
For the most part, from the air, the best luck I've had is to track the M4, and leave it. Occasionally scout for any M3's or jeeps that may try to run sups to it. So far that seems the best way to handle it until you get ord on site. Track it and leave it to others to finish off when they can.
As for on the gorund, I'll have to leave that to others. I used 3 new rounds from a T-34 to kill 1 Sherman in TT at close range, but that's the only real problem I had with one, and the local lag may have had something to do with that.