It might be because of your phone settings/permissions, incorrectly set Notification Widget, or just because there is a possible issue (others have had a few recent topics about this)… hard to say.
@Gunner this shows uptime of the device/sensor. but values or solid notification…
Blynk.notify(String("Running for ") + uptime + " minutes.");
This option will not work for me as I need a specific notification for specific room… on the Blynk app.
Another thing I will now use a professional Smoke Detector aka Genuine Fire alarm or a heat sensor to intrigate with this setup.