Toad 10.6.1.3 seems to have a bug where the "Automatically detect schema and name" check box no longer picks up the schema of the database object but only the schema that you are currently in.
Uncheck the box and put in the schema name of the location of the object or in the select statement, qualify the schema name then export dataset.
This working as designed. Confirm that you are not using a synonym that has the same name as the table being queried.
See example in the Additional Information section.
This can be proved by the following example: