After upgrading vRA from 7.5 to 7.6 several services show up as unavailable in the VAMI

After upgrading vRA from 7.5 to 7.6 , following services might show up as unavailable

advanced-designer-service - UNAVAILABLE

o11n-gateway-service -UNAVAILABLE

shell-ui-app - UNAVAILABLE

vco - null

Going through logs you might see following exception

com.vmware.o11n.sdk.exception.RestApiException: com.vmware.o11n.service.version.ContentVersionException: org.springframework.dao.IncorrectResultSizeDataAccessException: query did not return a unique result: 2;

nested exception is javax.persistence.NonUniqueResultException: query did not return a unique result: 2

To resolve, check the vmo_contentversioncontrol table in vRA's Postgres database to see if there is a duplicate __SYSTEM record. if so, remove the one with id = 2

This is how that table should look

Once the second id is removed , services should start properly.