I am updating custom fields in the opportunityproduct entity using odata. However every time my code attempts to update it receives an error

You cannot set both "productid" and "productdescription" for the same record.

I tried to limit the retrieve to just the custom fields, but this error keeps popping up no matter how I narrow the retrieval of data to be updated.

I also checked my plugins to make sure that I am not updating these 2 fields and thus contributing to this problem.