I mistakenly removed my Harmony Hub from my now development C-4 hub without reviewing the uses of it on other HE hubs, including my Lighting C-7 hub. I used the Harmony Hub to control some candle lights on my Study desk, using a custom command to turn then on and off via a Button Controller App.
Putting aside my own mistakes in not reviewing the use of the Harmony device on other HE hubs, I did notice that even when first opening the Button Controller child App, the Harmony Hub device did not show as offline in the description of the action, it was only when editing the action that it showed this state in the device label / name:
After clicking Edit Action the device listed shows that the device is offline.
I can now see that this is likely just a fact that the action description is just a collection of text recorded at the time the action is created, or some other reason for not picking up on the OFFLINE status. I'm not particularly worried about this, just wanted to point it out and see if there would be an option to indicate this issue earlier in the process of reviewing a Button Controller configuration.