Please check if you select the alert type of "Continuous Alert"
For Continuous Alert, if there are more than 5 alerts of the rule created within the last 60 minutes, our platform may block the these notifications from being executed. This mechanism is to prevent our servers being blocked by Google play, iOS store and email servers caused by spam messages. As you see from the trigger logs, some APP notification items are marked in red color which means the notifications for these ones were not sent or sent failed. I suggest to change the rule to "change-only" alert please.