The Thermostat Details timeline is not showing all the heat turning off events. See the beestat chart below and compare it to the energy monitoring chart below it. The energy monitor chart is monitoring the power to the heat pump compressor. This is a one stage heat pump so it has no way to modulate the amount of heat. It just turns on or off to control temperature. Notice it is able to maintain the setpoint temperature and the actual temperatures are fluctuating so it does not appear to be missing data from the thermostat. It’s just not showing some of the off events. The heat off events are generally around 6 minutes long.
The below image shows a zoomed in view of some of the times when the heat pump was cycling off and on. In this one I have added the furnace power (green) that shows the circulation fans was cycling on and off at the same time as the heat pump compressor.