My HVAC device is sometimes not shown as “on” in the real-time bubble view or device view, but the on and off events are properly tracked in the timeline and the usage is properly shown in the device-specific usage chart. See screenshots, which were all taken in rapid succession. This has happened in the past for a different device but it cleared up after some fiddling around.
Have you reported this one to Support?
I have this happen with several devices all the time. Usually it’s stuff in the kitchen, like the over or toaster oven. If I watch the real time bubbles, the other bubble will get really big, as if the device wasn’t detected. But later (like 10+ minutes later when I’m not using the device anymore) I can open the device in the device tab, see the power meter, and it will say “off for 8 minutes” so it’s definitely being detected, just after the fact.