Help with Sacrifice

The spell of sacrifice says that “boosted by death marked enemies”. Before sacrifice casts, my hero has 43 magic, and the 1st and the 3rd enemies are death marked. So sacrifice should give 7+2*4 magic to all other allies which would make my hero’s magic up to 58 but instead my hero’s magic ends up with 50, nothing boosted. Bug or I misinterpret the text.
Here are the pics.

That was good enough it appears…