When a CRM data stream is created from a custom object with custom fields, there will be an additional "_c" added after the field label. The resulting API name would be "<fieldname_c__c>".
This is by design as one of the reason to distinguish the standard fields from custom fields. The "_c" is coming from the custom field and "__c" is added by Data 360 after deploying the data stream.
In order to have a consistent naming convention, the following steps can be performed:
Once the data stream is deployed, all the fields will have only "__c".
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