Spells: Cannibalize not returning enough mana

[Polixa]

This is intermittent, but something approaching half the time.

When I cast Canni, I lose 50 health and occasionally see my mana jump 25, as it should be.

More often, I see mana increase by 7. Sometimes it will almost immediately tick up another 18, so just a display glitch. I am getting my 25 mana in 2 instalments.

However, and here is the bug, often it will tick up by 7, and then not tick up the missing 18. So My canni-dancing will give me 7 for canni, then 19 for the med tick, then 7 , 19 etc. It goes in streaks...if canni is going to short-change me on mana it will do it time and again.

If this was just a display bug I would expect a big catch-up of mana at some point but that does not happen.