Installation on solaris now uses svc to start opennms immediately after installation. At this point in time it is not yet configured. If it's an upgrade there probably will be a mix of old and new configuration files.
Starting opennms with the default configuration or a configuration mix may have a lot of side-effects like adding unwanted nodes to the database, creating a lot of alarms etc.
To prevent this I would suppose the following patch to solaris/install/postinstall to remove the automatic startup:
diff --git a/solaris/install/postinstall b/solaris/install/postinstall
index be9fa7f..1b693ad 100644
@@ -26,5 +26,3 @@ else
/usr/bin/su $INSTUSER -c "$BASEDIR/bin/install -dis" || exit 1
-/usr/sbin/svcadm enable $FMRI || exit 1