More detail would be helpful.
What kind of cmvs/how many slots? If multiple, does it happen in each slot? Do you have another game in one of the slots at the same time?
Did you clean the cart edges yet? If so how?
You could run a check on the game via the bios and see if it fails.
You could try and put it into AES mode, or a different region and see if i still happens.
Can you open the cart up and make sure the boards are seated in there correctly? Sometimes board flex can cause issues.