Selecting the Import (versus Live Query) mode for SQL Server Analysis Services Tabular Models produces unexpected results.
On the Navigator screen when selecting columns for import, if columns from more than one table are selected then the results is a cross join between the tables. As an Analysis Services source, the relationships are defined in the database and therefore the expectation would be for the result to be a product of those relationships. Creating a cross product result of the two tables defeats the entire purpose on the Analysis Services model.
In addition to being logically useless in almost all use cases, the cross product is also funtionally impractical as it exceeds practical memory limitations as well.