MessageCenter/Audit log enhancement. Trap Enabled/Disabled activity from the Action Manager/Trigger Actions. This activity should be present in the Message Center.
You should be able to see when these items get enabled or disabled.
This is also likely a BUG. Ask the Tigger Action behavior is odd when Disabled.
You can configure an Alert, assign a Trigger Action (Opsgenie SendHttpRequest in this example), simulate the action and it will send even when the Tigger Action is Disabled.
The Alert will also show this Tigger Activity as successful in the "History of this alert on this object", but it's NOT really working if the Trigger Action is Disabled in the Action Manager.