What reason(s) could cause full upper mouth implant denture to pop loose from the abutments on the right side?

You need to go back to see your dentist for a bite adjustment and possibly to change the strength of your clips.

There are two major reasons for the attachment to come loose on biting. First and most common reason is occlusion (scheme of your bite) which can be checked and corrected. The second is wear of the attachment itself which can be easily replaced. Both can be addressed by your dentist.