Sub Zero 532 ice maker problem

This unit is 10+ years old but has had both compressors replaced and functions well except ice maker
will produce ice and within a few days, the cubes are melted together. I had technician out twice and
repair was made and it functioned properly for awhile and then same problem. He had said there was a
missing screw which let the water flow down into the drawer and melt cubes together.

I'd like not to be out another $100 for a short term repair.

Any suggestions would be appreciated. Thank you.