Guillotine's signature ability is not healing by as much as it should be.

Mine is at sig 200, and so when health steal triggers, she should heal 54.99% of the hit's damage for every 4 souls she possesses, however she is failing to heal the correct amount at any amount of souls.
Here are a few examples:

976 damage, at 5 souls
This should heal 976*0.5499=537 health
but it's only healing by 214
Approximately 2/5 of what she should be healing.

1149 damage, at 18 souls
This should heal 1149*0.5499*4=2527 health
but it is only healing by 1004
Approximately 2/5 of what she should be healing.

988 damage, at 19 souls
This should heal 988*0.5499*4=2173 health
but it is only healing by 864
Approximately 2/5 of what she should be healing.

1630 damage, at 10 souls
This should heal 1630*0.5499*2=1793 health
but it is only healing by 713
Approximately 2/5 of what she should be healing.

283 damage, at 10 souls
This should heal 283*0.5499*2=311 health
but it is only healing by 124
Approximately 2/5 of what she should be healing.

2761 damage, at 17 souls
This should heal 2761*0.5499*4=6073 health
but it is only healing by 2414
Approximately 2/5 of what she should be healing.

1576 damage, at 8 souls
This should heal 1576*0.5499*2=1733 health
but it is only healing by 689
Approximately 2/5 of what she should be healing.

269 damage, at 9 souls
This should heal 269*0.5499*2=296 health
but it is only healing by 118
Approximately 2/5 of what she should be healing.

440 damage, at 10 souls
This should heal 440*0.5499*2=484 health
but it is only healing by 192
Approximately 2/5 of what she should be healing.

1802 damage, at 18 souls
This should heal 1802*0.5499*4=3964 health
but it is only healing by 1575
Approximately 2/5 of what she should be healing.

And finally, at no souls it should definitely be a heal of 54.99% of damage dealt.
That should heal 230 health, but it only healed 92
Approximately 2/5 of what she should be healing.
In each case, Guillotine is healing almost exactly 0.39749 times the amount she should be healing.
Approximately that's about 2/5 of what she should be healing.
Apologies if the amount of examples was excessive, but I wanted to provide as many different opponents and situations as possible, and provide a sizable sample of numbers to work with.