I'm going to say this in another way.
Most codes you hacked in the game memory ie ram rather it's through code searches on a code generator, or editing the memory in ram, to get codes.
Example: Zelda the rubies code, now you go to that address in the memory you can change it to whatever 066D ??
Obviously there wont be ?? there, but be in hex, and changing it will show it changing in the game itself, just the same as if you had it entered as a cheat and turn on.
As those that hack codes/ or use codes know if you enter that code as a cheat and turn it on, code effect would work, and also be highlighted in blue being the the digits part that changes how much rubies you have in the hex editor ie ram.
Now in Zelda 2, going to the games ram in the hex editor, changing the music with the music modifier works fine when changing it there, but when using it as a cheat and having it on just like the zelda rubies code.
Being that it doesn't trigger like it should to make it work when using it as cheat.
Most codes you from the ram will work as cheats, but some like the music modifier only work in the memory editor only, which they should be able to work as cheats, as other codes have.
As I said I've hacked a lot of codes over the years just using the memory editor alone, and all work fine using them as codes, no different then using the code search, I've done this hacking other emulators, but have only encounter this issue in this one, and those like it ie nes emulators that use pro action replay codes, and memory editing.
So it seems to only effect certain codes.
Also for the record it's not because its a music or sound modifier codes, I've manage to make such codes for other nes games with no troubles at all, but as I said seems 95% codes you get from the memory works in using them as cheats but some like the ones I mention only work in the game memory, and it would be nice if there was a way to fix this, if not well least I tried, but hopefully someone understands what am saying.