Refrigerator door seal is developing a gap towards the bottom. Not sure it is letting air through
The answer is found here:

How can I eliminate a gap in a refrigerator door gasket?

which points also to

How do I fix a gap in my refrigerator door gasket seal?

It is a door alignment issue.

Simply loosening the screws at the bottom on the hinge side and raising it a bit down there fixed it.