I have a Necromancer with 3 undead pawns. The undead upkeep cost is 0.570 mana with two levels into Cheating Death.
The description of Raise Dead states it should cost "30% of base mana regeneration for each undead, humanlike pawn." Base regen is 0.240, thus each should cost 0.72 upkeep maximum.

The weird thing is that it was working just fine before, I had 6 undead for 2 Necromancers and it worked fine, a Mana Drain hit, and then the upkeep cost has not gone back up. I am planting the Thorn bushes, but that is a separate upkeep cost.
Why is it so expensive and how can I fix it? I've tried reloading the save, and dismissing and raising them again to no avail.