Garmin cycling plan not showing critical pacing data

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 :)