Hi @Nikita Randive Thanks for using Microsoft Q&A forum and posting your query.
Looking at the error message it seems like the error is thrown by Dynamics CRM and nothing to do with Mapping data flow.
I'm not an expert with Dataverse (Dynamics CRM), but as per my research, but as per my research, the issue occurs if there is no/incorrect single-valued navigation property in the entity type. For more information about this error and possible solutions, please refer to this troubleshooting guide.
Troubleshooting Guide: Error identified in Payload provided by the user for Entity '{entity name}'
Here is a another Q&A thread where a similar issue has been discussed: Need single-valued navigation properties in OData for lookups
Related article: How to fix getting “Undeclared Property Error” when using Lookups with Dynamics 365 Web API
Hope this helps. And if you have further questions regarding this Dynamics CRM error, I recommend reaching out in Dynamics CRM community forum.
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