I see this has gone unanswered for some time. Did you get what you needed? If not, please open a ticket with Support for the Oracle KM team and they will be glad to assist.
Hi Abhay, I spoke with the Oracle KM team members and they indicated that Data Corruption cannot be monitored, but the Data Guard KM may be able to help somewhat
For the blocking sessions, it could be possible monitoring issues, here is a reference:
If this does not help, please open a ticket with Support.