I am having an issue where my newly favorited channels are not showing up in the guide under favorites on my firetv devices. These channels do show up when selecting favorites on the web guide. Do I need to do something special to refresh this list?
Favorites are not automatically synced. In the client device, if you go to Settings > Manage Sources > Source there is an option to sync the source. (This option is only available on Android devices.)
Or, the preferred option is to use Channel Collections; those are automatically kept in sync across all devices.