I wrote a custom connector to wrap PostgreSQL ODBC driver so that we can use DirectQuery (before 2019 August release). Everything works except this case:
1. Connector to data source via my custom connector.
2. Import a table, select DirectQuery mode.
3. Create a list, add a varchar column to list, right click a value and select "include".
I got this error: There is no row at position 16.
However, if I add another column, I can get data base without error.
I would suggest you to follow the doc ODBC Development troubleshooting and test . If this issue still persists, you can create a support ticket here.