Does Qiyana die when Stupefy resolves if she has 4 damage marked on her?

Ruling: Yes, Qiyana dies when Stupefy resolves. After Stupefy resolves, she becomes a 4 Might unit with 4 damage marked on her, and she dies during the cleanup that occurs after each card is played.

Sequence:

• Stupefy resolves, reducing Qiyana to 4 Might
• Cleanup occurs after the card is played
• The game checks for dead units during cleanup
• Qiyana has 4 damage marked and 4 Might, so she dies

Nuances:

• Damage heals at the end of combat, but this is irrelevant to this interaction since the cleanup happens immediately after Stupefy resolves