Tried it on several different minions, as soon as they’re full HP, overheal won’t be triggered anymore.
What card or effect was in play that you expected to be triggered by overheal?
Any overheal minion, I had many in play. They don’t respond to hero power, locations or funnel cake at all anymore once they’re full HP.
I guess they messed something up in the code when implementing the new overheal minion.