I seem to recall that in SF2:CE - in the Japanese versions, Boxers dash punches hit you when crouching, in the world and USA versions they whiff. Might need to check again, it's been a while.
View: https://youtu.be/WHs4gxwUKZY?t=2431
These barrels at this timestamp aren't in all versions of FF. Can be a big deal because they can have food in them.
Nice work man! Looking forward to seeing what you do for a 4:3 mask. I have one myself that is missing a mask and have been thinking about what I could do.
Looks like a ground loop. PVMs ground their video ground on the BNC connectors to frame (mains) ground. See if it goes away when you connect G (COM) and FG (Mains Ground) together on your power supply.