Immortalized enemy creatures still targeted by AI

[Billly]

I have cast immortality on some enemy creatures to stop them from being healed by the opponent AI, but it seems they still are. (it would be very useful against damaged Otyughs so that they can't devour my creatures) This looks like a serious bug to me.

[Uncle Jellyfish]

I'm guessing this was in PvP? It was a desync error. On your opponent's screen, you never made them immortal, so they were able to heal them like usual.