Umm... interesting.
So I tried again the same process you did with the same game: VC Sonic the Hedgehog 3, and IT WORKS!, no matter if I use d2x 10 (56), d2x 10 (57), d2x 10alt (56), or d2x 10 alt (57).
Tried also VC Enduro Racer (MegaDrive) and also works.
Tried also VC Golden Axe (arcade...