Correct!
https://learn.microsoft.com/en-us/azure/search/knowledge-store-projection-example-long#relationships-among-table-object-and-file-projections
If you don't want the data related, define the projections in different projection groups. For example, the following snippet will result in the tables being related, but without relationships between the tables and the object (OCR text) projections.
https://learn.microsoft.com/en-us/azure/search/knowledge-store-projections-examples#define-a-file-projection
File projections are always binary, normalized images, where normalization refers to potential resizing and rotation for use in skillset execution. File projections, similar to object projections, are created as blobs in Azure Storage, and contain binary data (as opposed to JSON).