I've had the abnormal (high) HR warning enabled at 100bpm since it was first supported and never had it go off until recently.
Now it's gone off maybe 4-5 times reporting 120bpm+ whilst sitting and a couple of those times I measured my HR using the sensor on my Samsung GS9+ phone, it reported the expected ~60bpm whilst sitting at my office desk during an alert on the FR945.
I could just be getting unlucky, but wondered if anyone else was now having false alarms also?