My theory: Once I used the spell to set Battlecruiser to 20/20, it no longer gained health, even though I had added more health using upgrades. This definitely affected my game and caused me to finish in a worse position.
visual proof: https://www.dropbox.com/scl/fi/l0hj51h6einvp0u4o3dnr/Screenshot-2025-07-19-at-19.51.42.png?rlkey=alwni9afdmuwnrlezaj9mbho3&dl=1
on Mac Sequoia 15.4.1 (24E263), with Hearthstone Unity Player version 2022.3.52f1 (1120fcb54228)