I started a cycling plan and today I had my first proper session, for the purposes of explaining this was the plan:
Warm up: 119bpm
Tempo: 169bpm
Rest: 119bmp
Cool down: 119bpm
The middle two being repeated 3 times.
The thing is, the heartrate guage on my screen worked, but the target heartrate was not showing at the bottom, only when I got close to the range. This might sound easy to fix, but when i am changing heartrate this much, i can be 60 beats a minute either side of the target, which is excessive.
I tried to change the screen during the activity, to update the target, and this worked once but then never again.


Above: shows the gauge working at the top. The bottom number "0.00" is where the target should be.

Above: showing the alert, which also shows the target, but only on the quick apert popup, and only when you are within 10 beats of so of the target anyway.

Above: the graph after, showing that the target was always available to the device, but for whatever reason, it wouldn't show on every part of the watch screen.
I hope this is thorough enough :)