Hi @NathanPzi ，
Depending on where you create the calculated column; they can have some limitations. If you create a calculated column in an Import table or a calculated table, then there will be no limitation. However, if you create a calculated column in a DirectQuery table, then in the expression for the column only columns from the same table can be used.
Composite Model in Power BI; DirectQuery and Import Data Combined - RADACAD
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