First and foremost, it must be said that the AlarmConsole portlet in UMP is currently (As of the release of UMP 7.5) deprecated - one major reason for the deprecation of this portlet is that it is known to be unreliable and suffers from synchronization issues - it should be expected that the synchronization between AlarmConsole and IM/NAS will never be perfect, and customers will have a generally better experience using the Alarm Views in USM.
The following information may be useful for minimizing this problem but is not likely to eliminate it completely.
Alarm processing and display in the AlarmConsole portlet is the responsibility of the dashboard_engine probe. ? The dashboard_engine contains something called the Alarm Processor which can be tuned or adjusted to some extent for better performance.