Siphon bullets make enemies invulnerable when their health is reduced below 0

[FaxMeDarling]

When i drain an enemy's health by killing them enough times to reduce their max hp below the range of a siphom proc, i can no longer kill that enemy. It seems it first applies siphon, then checks for damage, and i guess things that have 0 or negative hp just can't take damage.
Could it be that if siphon reduces the enemy below 0 and damage is clamped to never reduce the characters below 0 hp. As a result enemies take 0 damage while having negative hp and i guess skipping death checks?

 

[FaxMeDarling]

Ok, so, I cheked, it seems that it only happens when the enemy took 0 damage and has negative max hp. Realistically this should not happen, but i think it may be possible with someone like victor or viscous that can easily heal. My guess is that damage is stored as an integer, so it's x damage taken vs max hp. While damage is at 0 and max hp are negative some check fails and the character doesnt take damage at all. If the enemy with less than 55 hp takes damage, then is killed with a siphon, it goes under 0 as base max hp and is absolutely immune to every form of damage.

 

[max36]

I managed to (accidentally) replicate this with the Seven standing in the atrium. Siphoned 12 Stacks.

 

[gwendoodle]

I recreated this as well.

I've Tried Geist and Shiv ults as they do percentage damage and it didn't even show damage numbers nor play a damage sound.
Love Bites, Lethal Venom, and Fixation all no longer activate their on hit effects. Abrams here is completely immune to any debuffs aside from Mo&Krill 1st ability stacks (image included).

However, using Mina's ult for the built in silence IS causing the particles to appear as though Abrams is silenced. Similarly, Haze's sleep dagger is able to visually affect him, even if there's no debuff icon.

Couldn't this be fixed by setting the minimum health to 1? I mean that would obviously be unbalanced but it would solve this problem. Alternatively making Siphon Bullets unable to lower an enemy's health below 5~10%