3D Print of 12MM RAPID FIRE DICEBOX

Loving this build! I used a Neptune 3 Pro using the Elegoo PLA+ in hobby grey.

I have a bit of a question about something that seems to have happened on some parts which hasn't happened to me before so I wonder if any one has any advice. Thankfully it doesn't really impact the functionality of this print but for the future and before I print the scenery version. On three of the parts they are not flat and one has a raised/corner.