On Tuesday morning I powered off a number of devices in the home and only restored power this afternoon (Friday).
In the intervening period the mobile app had flagged thirteen devices as being offline, and a custom app that reads the device health from the API showed the same thing. However even allowing for my not having turned off all the devices that I intended to, five other devices that were powered off were never marked as offline.
Four devices were Meross Matter over Wi-Fi smart plugs. They also reported 0 W for the Power Meter capability in details page of the app, though no such figure appeared in the history tab.
The other devices was an Eve Energy Matter over Thread smart plug. That reported 29.1 W for the Power Meter compared to 29.2 W in the history tab.
At approximately 9:30am (GMT+1) I powered off four devices (Living Room Cabinet Fairy, Living Room Window Fairy, Living Room Seasonal and Bedroom Fan) and dumped the logs (getting one device name wrong in the comment).
There would actually have been a short delay as I moved between rooms, but only a minute or so. I think I did the Living Room devices first and then briefly contemplated whether to add the other one.
Minutes later I opened the mobile apps and all four devices were already showing offline, which is pretty quick work.
Around about 9:39 am I noticed the Bedroom Fan had stopped being reported as offline. I can assure you it is as it is unplugged and sitting on the carpet.
After typing the above, at about 9:52 am I noted that the other three devices were no longer showing offline and logs were dumped c. 9:55 am.
It turns out the timeline actually looked like this to a subscribed SmartApp:
2025-09-09T09:30:46+0100: Living Room Window Fairy OFFLINE SERVICE_UNAVAILABLE
2025-09-09T09:30:46+0100: Living Room Cabinet Fairy OFFLINE SERVICE_UNAVAILABLE
2025-09-09T09:30:46+0100: Living Room Seasonal OFFLINE SERVICE_UNAVAILABLE
2025-09-09T09:32:00+0100: Bedroom Fan OFFLINE SERVICE_UNAVAILABLE
2025-09-09T09:39:40+0100: Bedroom Fan ONLINE NONE
2025-09-09T09:40:51+0100: Living Room Seasonal ONLINE NONE
2025-09-09T09:40:54+0100: Living Room Window Fairy ONLINE NONE
2025-09-09T09:40:57+0100: Living Room Cabinet Fairy ONLINE NONE
So my suggestion in the original post that these devices were āneverā marked offline is probably incorrect. It would appear that in fact the devices do get marked offline very shortly after being powered off, but then they incorrectly get marked online again and stay that way.
Just for completeness, these devices are on multi-admin with Google. Google knows they are offline.
Oh and I note in particular that these are the only types of plugs I have with power/energy reporting.
The Bedroom Fan has been powered back on. The others remain off for the moment.
I had something similar last night. Normally 3 zigbee switches (which are only turned on at night) are turned off at the same time and gets reported as offline, but they remained online for a period and I had to double check that they were indeed switched off, which they were, whilst being reported as online. I closed and restarted the app a couple of times before it correctly reported the switches as offline. Itās looks to be fine since (i.e. all 3 remained offline).
Thanks for sharing these details.
To help our engineering team investigate this further, could you please repeat the test and capture the hub logs at two points:
Right after the switches are powered off.
Once they are finally reported as offline in the app.
Select the time period and confirm - In this step, please select āUntil turned offā, once the team finishes, weāll let you know so you can disable it again.
I had similar experiences over the last couple of weeks, and what I experienced today was particularly confusing.
Since I faced some troubles with the stability of the SmartThings system, I unpowered the hub AND all permanently powered Matter-over-Thread devices (which are, in my case, 3 Eve Energy plugs) - in order to completely restart the whole system.
I connected the hub to power again - in order to see which battery-operated Matter-over-Thread will return back to the system without any Mesh devices supporting the Thread network. Therefore, all 3 Eve Energy plugs remained disconnected. However, after a couple of minutes, they are suddenly shown as online - even though they are not even powerd?! The driver seems to be the latest one available: āVersion 2025-09-10T19:04:43.025892689ā.
I did all of that for the reason that some of these plugs were shown online, yet unreponsive through the SmartThings app. As these ones were used as Mesh repeaters for contact sensors, this is particularly frustrating as most of the components connected to the system were not working any more.
The three Meross Matter over Wi-Fi plugs that I have left switched off for the last couple of weeks are now showing as offline. It looks like my hub went offline early this afternoon, causing all the hub connected devices to be marked offline, and when it came back again those three devices stayed offline. The hub has previously been rebooted and those devices have been showing as online afterwards.