The bot does not currently handle this card well when it plays against it. It will try to chisel away at its health like any other mob which is bad. It should only really attack grim patron if it can deliver a deathblow.
I've noticed it doesn't seem to play the card properly if it's in your hand either Most of the new cards and some of the old ones need a tweak.
(ง ͠° ͟ʖ ͡°)ง (ง ͠° ͟ʖ ͡°)ง EVERYONE GET IN HERE (ง ͠° ͟ʖ ͡°)ง (ง ͠° ͟ʖ ͡°)ง We'll be making some adjustments to these new cards as time goes on. This one will definitely be higher priority now. Thanks for reporting it.