In ALM 11.00 and above, if you modify entities via ALM Synchronizer, not all the modified entities will trigger the relevant alert rule.
This is a known limitation, caused by the multi-threading mechanism of alert sending. This can be seen when a bunch of entities are modified by an application or a script, such as ALM Synchronizer.
We’re going to have a fix in the next version of ALM Synchronizer. Regarding other applications or scripts, our suggestion is to wait for a few seconds (3 seconds recommended) before logging out the ALM project, after the entity modification is done. This will allow the alert-sending thread to finish its work.