So I went reserve on the scav, I don't play scav really much I only really play PMC. But my friends were in a raid when I joined so I went scav reserve. I find Glukhar and his guards, loot 2 PMC's they killed, hang around. Another player scav pops along, kills a guard, gets blasted. I loot em all.
Glukhars guards start getting shot at from across the way, they all go aggro to go return fire and I see where the shooter is. I kill him, he definitely hit the guards, and he was definitely a low karma scav since he musta known they were guards and went for em.
I take a -2.1 penalty for doming him, only to then get promptly put down by one of the guards.
I don't really care because I was nearly 10 rep, but that's really dumb that I can't defend the boss without waiting for one of the guards to actually die. HItting a guard should be enough to flag you as hostile for me to eliminate you with at least no penalty.
Source: https://www.reddit.com/r/EscapefromTarkov/comments/qxnvwi/losing_karma_for_defending_the_boss/