Cloud Control shows databases down while they are up
I have a Cloud Control installation 13.3. it is monitoring a server with 6 databases 18.3.
Yesterday I shutdown all 6 databases to install a patch. Now they are all up.
However Cloud Control shows that 4 are up and 2 down. But when I click on these databases in Cloud Control everything seems to work fine although there is down arrow.
Also Oracle Database -> Target Setup -> Monitoring Configuration - Test Connection I get "The connection was successful".
Why they appear down? How can I troubleshoot?