[Discussion] Enemies immortal last 15ish minutes on Customs? (PVE)

Had this happen a couple time now, where enemies (both SCAVs and PMCs) in the last 15ish minutes are immortal. Loaded full magazines of the Hybrid Spear ammo into a PMC or SCAV's head, and they don't die. Gets to the point where I have to just run for my life and hope I don't get a random bullet to my head as I try to extract.

Anyone else run into this? Only has seemed to happen on customs, and only when I'm in duo's any my partner died.