Played against a dk that had played headless horseman but had not drawn the head yet. On their turn with screaming banshee on board they drew the head and screaming banshee spawned a 17/17 minion with no healing done.
There seems to be something buggy with how Screaming banshee interacts with max health buffs because Maw and pa had given +10 max health and primus gave +7 to make the 17/17 that spawned make sense
I can confirm this as I encountered almost the same bug.
In my case, I played Reno hero card with “Screaming Banshee” on board and it generated a 10/10.
I had gain HP twice before that with “Maw and Paw”, so I think you are right about the cause.
Its currently October 14, 2024. I can confirm that this issue is still going on via wild format.
I guess we can consider this a feature
This bug still exists. I played a Reno while I had a Screaming Banshee on board. Summoned a 10/10. I think it’s because I played Airlock Breach that brought me to 40 max hp. Probably I temporarily went back to 30hp, then to 40hp.