Below is the Pattern detector report issue:
The /oak:index/xxx Oak index has a rule violation: type property value must be luceneMore info at theKnowledge Base
Referenced by: /oak:index/xxxReferencing: type property value must be lucene
1) Is it required to fix the issue while migrating from 6.4.2 to 6.5.7?
It is better to address critical issues during upgrade.
did you try applying type "lucena" in oak:index , any issues?