2658508 - OData Error: Illegal JSON string-value format while executing an UPSERT operation on an ODATA Entity

The following error occurred while executing an UPSERT operation on an ODATA Entity:

<d:message>Illegal JSON string-value format</d:message>

"Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental."

SAP SuccessFactors HXM Suite

- OData Entities

Illegal JSON string-value format, UPSERT, operation, double quote, JSON, error, OData, POST , KBA , LOD-SF-INT-ODATA , OData API Framework , LOD-SF-INT , Integrations , LOD-SF-INT-EC , Employee Central SFAPI & OData Entities , Problem