I waited to report this until it happened a third time, since I incorrectly thought it was only happening in one particular User App.
STEPS TO REPRODUCE
- Open Devices ► click on child device of any User App (e.g. "The Computer" created by Wake-On-LAN);
- Scroll down to Parent App and click link to visit Parent App;
- Observe that device is currently listed with Name and other details (see screenshot);
- Click the Child Device's entry in list, then . . .
- . . . click blue 'Cog' icon in upper-right corner of screen (see screenshot);
- Click "Back to App" button;
- Observe that same device now has (null) for Name and (possibly) other details lost (see screenshot);
- Click Devices, and observe that Child Device (e.g. "The Computer") now gone.
Seems to be about 100% repeatable, and has now happened to me in both the "WakeOnLan" and "PC Controller" user apps. FYI, I'm in 22.214.171.124 at the moment. Fortunately, returning to the Parent App and re-entering the device's Name restores it in Devices (and presumably it remains connected to all existing "In Use By" apps, although this is untested by me).