Aeotec HEM Gen 5 + Raspberry Pi4

Raspberry Pi 4
Aeotec stick Gen 5

When initially installed the readings from the HEM made no sense. The measured current seemed low, kW made no sense and the device was constantly going off-line.

With the raspberry pi on the workbench, the stick was being de-sensed by being surrounded by cables and monitors, so relocating to a clearer location solved the off-line errors in the log.
The current issue was a bit trickier to solve.
It turned out that the 60 amp clamp was too snug a fit on the house mains cable, stopping the ferrite inserts from making clean contact against each other. Luckily it is possible to trim excess plastic from inside the clamp housing without damaging the insert, allowing the two halves of the ferrite to engage correctly with each other. The current readings from the HEM are now very close to my True RMS clamp meter, and the sensitivity of the HEM restored.
Hope this helps anyone else with similar problems.