Creating Sync Views across Multiple Sync Sources in EDA - Administrator

I am attempting to create a custom View (or table) from the EDA - Sync Sources page, and running into challenges when joining tables from different sync’d sources.

I am finding that if the joining table has a single relationship (ex product_id = product_id), the query will execute with expected results. If the joining table has multiple relational attributes, the expectation will fail. (ex. customer_id = customer_id AND product_id = product_id). I have tested this on multiple sources and fields, and have also casted and converted data types to exclude that from the underlying problem.

Has anyone run into similar challenges, or have any suggestions? Any insight is greatly appreciated!