When the wither gets in a minecart while "powering up" it does not continue to gain health.
Linked issues
Comments 4
Hmm. he didn't disappear when i tried it. he keeps the health he had before he got into the minecart, then he destroys the cart with the explosion, still having the amount of health he had when he got into the cart.
This ticket has been marked as a duplicate of MC-8487, in favor of the better description/information provided.
Confirmed.