[The Old Guy]

Yes, I have had same problem. Had it in to two different shops, both said it was fixed, neither fixed it. Sorry I don't have an answer except to keep a thermometer in there and turn it off when it gets to 30 or 32 degress, trun it on when it reaches 40.
Difficult to control if you are out for the day, I let it get down during the night and try not to open too much in AM (ha).

Not a good workaround, or cure, but... PS, there is a slide on the fins of the unit, inside below the freezer. Supposidly sliding that up or down changes the temp in the box. Did not work for me.