December 2018
Once again I tried to post this under bug reports but it will not allow me to post so putting it in General Info.
Basically when a medic was reviving a player on a hill/embankment/mound/whatever you want to call it, the player was receiving no damage and was completely invulnerable. I have attached a clip of this happening on a Grand Operations server during the Airborne phase. See from :16 - :30
December 2018
This is a common problem with bullet collision, which usually happens between the two players. Bullets aren’t relaying information back to the client fast enough for them to cause damage to the other player. Although I believe this is being worked on, I also believe it will never fully be resolved, due to individual player connection speeds.