Duplicates on table due to relationship model

You really should fix your model.  Many:Many relationships with bi-directional filters is a bad way to start learning Power BI.  Making a Master Table is a good idea, and you should transform that to make it so it can be on the 1 side of relationships to the other two tables.  The concatentation is a good way to do that, and I expect the model simplicity would far outweigh the file size impact.

Ok.  Off my soapbox, here is an expression that gets your desired results.

New Measure =
CALCULATE (
    SUM ( Query1[Units] ),
    TREATAS ( VALUES ( 'Master Table'[Location] ), Query1[Location] ),
    TREATAS ( VALUES ( 'Master Table'[Site] ), Query1[Site] )
)

Note that this a work around for not having a proper relationship (back on my soapbox I guess).  The two TREATAS clauses pass the filters that a concatenated relationship would have done automatically (i.e., your measure would just be SUM(Query1[Units]).

If this works for you, please mark it as the solution.  Kudos are appreciated too.  Please let me know if not.

Regards,

Pat