Alarms are not being raised on some device models.
Customizing certain System events will cause this issue. The following link shows a list of events codes which should not be customized
TechDocs : DX NetOps Spectrum 21.2 : Event and Alarm Customization
DX NetOps Spectrum Release : 20.2 or later
Component : Spectrum Alarm & Event Management
Check if there is any customization of the events which are documented NOT to be customized in the custom directory Event disposition file:
If the event is customized as follows:
0x00010d35 E 75 A 3, 0x00010009,N
Then this will make the alarm User Clearable which can cause a problem with Spectrum's inference algorithm if the alarm is cleared.
The alarm generated by the 0x10d35 event code should not be User Clearable.