I wasn´t playing for 2 weeks. Now me and a few mates played a few hours. Everyone had the same problem from time to time: you shoot someone, you see the hit indicator at the crosshair, but the health is not decreasing correct. 2 weeks before, before the patch, it was ok. We tried a few servers, ping beyond 50, and we are not living in the same city, don´t use the same ISP/Backbone.
Someone with the same problems?
[PC] Bullets disappear since patch?
It could be that the players you hit had the Adrenaline buff - although they would have taken damage once the buff wore off, if that was the case.
Good point, but we´ve played more then 80hours each, we see the yellow adrenaline box 
Additional, it was “normal open world shooting”, no Medic who got close to the ones. For example, i followed someone, around the corner he stood alone in front of me, was running around the next corner, minimum three hits with the cross, got hte hit indicator feedback. One step he was out of sight, as i was around the corner, the soldier was at 100% life.
Of these moments i had more then half a dozen last evening.
you’re absolutely right, the hit detection is way off and I’ve uploaded a video http://www.youtube.com/watch?v=plhyhdUz6VI