You can easily add delay. Like:
push ix
pop ix

This sprite glitch may happen only on low cost z80 include in lot of SMS 2, it may have no problems on SMS 1.

Hey, gave you an answer on smspower but as I get censored there for all my new messages, here also my answer: Your accessing the VDP too fast, I think that's why you have garbage on your sprite. In Emulicious Debugger, down middle choose Exceptions and then check Break on invalid VDP access.

ça vous choque pas plus que ça que quasi tout le monde garde son blouson ? Faut peut être mettre le chauffage ou un vestiaire à l'entrée.

Nice find! Are you gonna share the rom anyway ?

Sorry I had to.