Hello,
This issue seems to be present when the time that the device is offline is quite short, and RMS receives information that the device is online before it has time to process the Online → Offline action. As some users try to use as little data as possible, these checks cannot be done very often.
As the alert functionality should be fully transferred to the new "Alerts & Automations" module, it may have different behavior in these situations. There is also a suggestion registered to add a delay option for these alerts, which should avoid such behavior.
Hope this helps!
Best regards,
DaumantasG