The max health IS scaling correctly, the problem is they start with their base health value, so "Execute" cards will generally kill because the enemy starts at 40 HP out of their max 750 HP (random values for example sake).
This is noticeable if you allow the enemy to use drain spells or healing.
I did find my issue as to why they happened, they are supposed to heal to full at beginning of combat, but it was removed by accident while I cleaned up some stuff.
And the submissive state granted is name only. The effect you need to look at is the players one. (Since enemies can’t have special effects like that, so it’s a work around to kind of make it happen.)