It has been over 9 months since you were made aware of this issue. It has been nearly a year since it first started happening. When can we expect a fix for this? Also you are still pushing out the bad firmware causing this issue. I had mine working fine and not long ago it updated again and all my devices disappeared. Luckily, I had saved my configuration and was able to restore it.
Side note, I have found a way to "fix" it without a factory reset. IF you have your gateway working properly, from the main screen after you login, click "SAVE CURRENT CONFIGURATION" and save the file it lets you download. Keep this file in a location where you can be sure it will be safe. If they push the bad firmware again that stops connected devices from showing... just login to the modem and click on "RESTORE SAVED CONFIGURATION". Browse to your saved file and then click RESTORE. It will reboot the modem and take a few minutes. After it comes back online, all your connected devices will be showing and all configuration changes you had saved previously will be restored.