Hmm. Some progress, i'll report this over on CQC in case it's a CQC thing, but as I have HA02's that work fine, I doubt it.
The new HA02 appliance modules result in an error state if i set them to poll. If I don't poll them, they work fine. The old ones work perfectly though.
ChrisWalker - if you're reading this, do you know if the firmware was updated recently on these? Dunno why 2 old ones would work fine, but 2 new ones don't.