We went with the Xbox version, it only soul charges when we a) pull the right trigger, or b) press all three buttons somehow. Most of the time it behaves.

I don't know why yours soul charges, but have you tried changing the default control setup? Perhaps a diff config won't charge all the time.

Ivy is still my girl, I give Carlo a run, even when he's Spawn, and has been playing way more than me.

Isn't the game fun!