Damn! That is some grade A homework, man, lol! Tnx for finding that info!
Awesome finding, Mr. @Wiimpathy!It's not a bug, the palette changes on a real snes too. Look at the manual, Superscope section on page 5 of this pdf: https://www.gamesdatabase.org/Media..._Arcade_Game_-_1993_-_Ocean_Software_Ltd..pdf
For the curious and fact checkers , i corroborated real hardware behavior, here.
Setting up the needed things:
And the 1st level:
Normal pink hue!
Quoting the manual: