Filter Error on REST External BAQ

I have an external BAQ that is pointing at a view from an external DB. It runs fine in designer but when I execute the BAQ in REST with a filter on CustID or all . I get the following error.

  "HttpStatus": 400,
  "ReasonPhrase": "REST API Exception",
  "ErrorMessage": "An incompatible primitive type 'Edm.Byte[Nullable=False]' was found for an item that was expected to be of type 'Edm.String[Nullable=True]'.",
  "ErrorType": "Microsoft.Data.OData.ODataException",
  "CorrelationId": "dc8c4b3b-f62c-4059-b317-a633c5d4c662"

I tried altering the view and adding ISNULL on the CustID column which did change the property in the SQL view from null to not null but I still getting the same results in REST. Any ideas on how to fix?

Since it is an External BAQ, you may have to do quite a bit with the column types in Epicor. It may be easiest to change the field attributes in the BAQ though.

How exactly would you do that in this scenario? Create a calculated Field and try to do ISNULL for the CustID field?

That would be a reasonable attempt. From what I can gather, the External BAQ needs to know how to treat the fields, otherwise, it is straight SQL field types.

I would try to create calculated field with type string and make explicit conversion of whatever you have into string

Adding the field attributes with the same format seems to have worked. Thanks