Is Count Geonor (Final Act 1 Boss) bugged?

Hi, so I tried to do a Hardcore Run and I will ill prepared for this long battle with the boss, and everything was going great, until he hit 25% and I got a debuff that kept lowering my HP and nothing could be done to stop it, I was like crazy clicking the healing flask, but it was going down fast, I had 600hp at that point. It looked like a Chaos DoT debuff, but when looking at the boss abilities, he does not do any DoT spells, thoughts?

You got hit by the red ray. It makes you bleed. He casts those at first during the same time as the blue/cold rays. However, those then get cast persistently without him doing anything. Need to be super careful, that DoT is pretty strong and stacks.