8.6.1 is 8.6.01
This issue is a defect in 8.5 .x version and fixed in 8.6.x version which means it is fixed in 8.6.x version of BDSSA.
If you want to upgrade to 8.6.1 version, you can upgrade or if you want to fix this error in current version, you can follow the steps in provided in the KB article. It will fix this ETL error in current version 8.5.x
Defect QM001830169 was deferred and is now targeted for BDSSA 8.8
Meanwhile, the solution in this KA is still usable:
BDSSA ETL error: ODI-1217: Session 5_MDM fails with return code 1427 Caused By: java.sql.SQLException: ORA-01427: single-row subquery returns more than one row