Casting Imbue champion from a solo champion alone as a stack but standing in the same space as a second stack - 1 recruited champion, It asks to cast give up four essence, then asks it again, then crashes the game. 

Unusual situation I know, caused by one unit walking to a different location to the channeller landing on the same space and making two stacks. Then the champ sent to the channeller to be imbued joining the wrong stack. Imbue cast after still moving figure ejected from stack and sent along. By a glance it is caused by the spell trying to apply to the channeller. Then again a selection button for the target inside the stack for giant strength and Imbue would be helpful and stop wrong targetting.

http://pastebin.com/fDkS1YS9