I have several P110Ms connected to home assistant using matter, all running firmware 1.3.0
I’ve found that they show the “energy” sensors under diagnostic if they have access to the internet. If they are unable to phone home for an extended period of time (I have yet to determine specifically how long), the energy sensors will become unavailable.
This isn’t great, and I hope they are able to release a firmware update that removes this dependency. I have the previous generation P110 plugs (non-matter) from which I am able to read the energy values, even without an active internet connection for an extended period of time.