I have the same issue. Could someone help? we are with Ignition 8.1.17
I moved your question into a new topic because that other topic specifically dealt with the inability to acknowledge an alarm whereas your question seems to involve why an alarm is no longer listed. Since you're original posting was in a topic tagged as perspective, I've added that tag here as well and I'll try to answer as if you're using Perspective. If that's incorrect, then we can change direction later.
This depends on what filters you have applied to your Alarm Status Table, so we'll likely need some screenshots in order to assist you. Supposing you do NOT have Cleared, Unacknowledged as an applied filter, I would expect your alarm to no longer be visible in the Alarm Status Table.
Note that your alarm has not been "acknowledged", it has only become cleared (condition off, or "inactive").
Alarm Active (and filtering for Active, Unacknowledged):
Alarm Cleared (and NOT filtering for Cleared, Unacknowledged):
Alarm Cleared (and finally filtering for Cleared, Unacknowledged):
