Query definition: column ambiguously defined

When there are two columns with same name but with different table alias, i get this error.

For example, i have two columns in my query "Results Fields" with T3.EXTERNAL_ID and T5.EXTERNAL_ID. This results in this error.

ORA-00918 column ambiguously defined.

If i remove one of them, everything is perfect. Even if I replace table alias with actual table name, it is same. I'm wondering if anyone has workarounds or experienced this issue before.

Thanks!