Yes! The protector is made out of paper. I nearly had a loss once with Drow AFK antagging, so we had weaker spawns. One mistake caused the 2 of us staying near him to die and the group of grunts that jumped on him nearly wiped him out before our other 2 players could get there from the midpoint, he had a sliver of health left from just maybe 2-4 seconds worth of grunt attacks, probably 4-5 (weakened) grunts no elites. When Hades first launched he seemed to just die every time, it took a few updates before we were able to reliably finish the damn mission.
Agreed that his shield should be more durable, but the issue there is then it would be next to impossible for him to die, since he gets picked right back up into shield mode regardless of getting 1 aleph or 5. He needs to scale health and shield based on MMR, or something. He seemed to get a shadow nerf when Hades started, it's not just players that kill him fast, AI will tear him apart FAST.