Unkillable raider on lab

Hello. So, yesterday I was playing with my buddy on lab. We were decently geared, nothing special, definitely not naked though.
So we walked close to the “conference” room when we heard noises of a raider from inside that room. We backed a little waiting to see what the raider would end up doing since he was moving.
All of a sudden, while we were aiming at the door my buddy got shot and killed and I noticed that the shots that killed him came from inside the room, through the walls, since the door was still closed.
All of a sudden I saw the raider proning through the door, with he door still closed and then having the door opened, after he was already through it.
I backed again, and got cover. He started moving again and as he did so I got the chance to empty 1 60 round mp5 magazine (pst gzh) on his face. I 200% got him, as there was blood everywhere on the sass of the conference room.
Got to cover again, reloaded and as I heard the raider moving I got out of cover and shot hm again. It was 50/50 between his chest and his head this time.
He was moaning as the bullets reached him but nothing more.
Quickly got to cover again and reloaded once more with yet another 60 rounder.
The scav turned his back on me, walking away and again, I tried emptying my last mag, at this point realizing he was totally bugged. This time around after 25ish shots he turned his back again, looked at me and managed to hit me.
I gave up, backed and rushed away healing.
So while all this was happening the servers were totally fine, no lag, no desync.. nothing (was even using fps2 command).
I was still able to talk normally rough discord with my buddy.
It was really as if that scav was bugged and had infinite hp somehow.
This has never happened to me on any map, without he servers dying. And I found it extremely tedious quite honestly.
Has anyone else experienced his same thing?
Hopefully this will get looked into.