Cobra strike bug?

Hi, I’m currently playing Mosaic sin in the ladder S4.
I was wondering if there’s a bug when you use Cobra strike Charge#3 with Tiger strike Charge#3.

The thing is that Life/Mana stealing seems not working frequently when I use a combination of 2 PS + 3CoS + 3BoI + 3TS + 3CS.
If I use the same combination of skills but 1TS instead, it seems normal. Is it also same for you? Is there something wrong with the combination?

Thanks in advance:)

It’s an overflow bug.