We have checked your query and we have prepared a sample as per your scenario. In the sample, we have used 45 columns and 1000 rows in SfDataGrid and the reported issue is working fine in our side. We have attached the tested sample and please revert the modified sample based on your application with the replication procedure.
Note: In SfDataGrid, it is not possible to give same MappingName for two or more columns.
Sample Location: Column_Types
Regards,
Srinivasan