Tip: If your level contains elements that temporarily change the music to a global song (such as a P-Switch or a Star), that music will not stop playing after the intended end time if the music bypass setting is set to 00.
This only seems to correctly set the Yoshi coin icon if I've just entered and left the stage in question, otherwise the icon is always empty when moving around on the overworld, even if I have all the Yoshi coins. I'm using SA-1. Any idea why this might be happening?
EDIT: I ended up using the "Yoshi Coin Checker" UberASM instead, which places the same icon but works correctly for me. Not sure why this patch doesn't.