In case you guys didn't notice, I'm devoting the majority of my testing to ensuring older quests work under 2.5.
Here's another strange bug I found while playing through the O3Q:
Before:
After:
The best way I can describe this bug is whenever Link gets hit in a Zelda 1 Level 3-colored dungeon it is treated as though the "No Level 3 CSet fix" rule is enabled. It isn't actually enabled of course, but the effect's the same. However it only seems to happen if Link has the blue ring or greater. It reverts back when Link enters a passageway. Should Link get hit inside the passageway it happens as well. I was able to duplicate this bug in the latest version of my test quest, available here. It now has a Level 4 cheat code ("cheat"😉.