Ziggurat boss becomes unkillable - with steps & tests

Update

After playing more of Ziggurat, I noticed that the "Melee" part of VLS was making a hit sound when the boss goes into it's add phase.

I then decided to try putting my VLS in the edge of the room so only the projectiles will deal damage, and so far I haven't run into the problem where the boss becomes invulnerable.

So I'm guessing the Melee hit from VLS is causing the issue.

I'm currently playing a perma VLS build and i spamming it in the edge of the room, so i dont think "insane amount of damage" is the issue.

Just happened to me. Nice to see this was posted in 2024 and not fixed. RIP giga juiced t17 map because I portaled out in boss arena instead of logging out.