Disabling LED DEVICE does not set LEDs to black prior to disabling

[tavalin]

Bug report, debug log and your config file (FULL LOGS ARE MANDATORY)

Steps to reproduce

1. Running HyperHDR v18 Beta2 with ESP32 flashed with HyperSerialESP32_SK6812_NEUTRAL_WHITE_FIRSTLED_ENABLED.bin
2. HyperHDR receiving data via FlatBuffers from LG WebOS TV
3. Turn LEDDEVICE to off from the remote tab

What is expected?

Disable LEDDEVICE sets LEDs to black/power off

What is actually happening?

LEDs remained lit with last frame colours.

Log suggests the LEDs should be being powered off but this does not actually happen.

2022-05-09T17:47:37.105Z [LEDDEVICE_ADALIGHT] (LedDevice.cpp:135) Disable device
2022-05-09T17:47:37.105Z [LEDDEVICE_ADALIGHT] (LedDevice.cpp:200) Stopping timer
2022-05-09T17:47:37.105Z [LEDDEVICE_ADALIGHT] (LedDevice.cpp:335) Switch off
2022-05-09T17:47:37.105Z [LEDDEVICE_ADALIGHT] (LedDevice.cpp:293) Set LED strip to black/power off
2022-05-09T17:47:37.106Z [LEDDEVICE_ADALIGHT] (ProviderRs232.cpp:90) Flush was successful
2022-05-09T17:47:37.106Z [LEDDEVICE_ADALIGHT] (ProviderRs232.cpp:92) Close UART: ttyUSB0

LEDs remain with same colours as last frame received.

System

HyperHDR Server: 
- Build:           (HEAD detached at d7e3117) (Awawa-bba94d0/d7e3117-1651692977)
- Build time:      May  4 2022 19:42:37
- Git Remote:      https://github.com/awawa-dev/HyperHDR
- Version:         18.0.0.0beta2
- UI Lang:         auto (BrowserLang: en-US)
- UI Access:       default
- Avail Capt:      Linux (V4L2)
- Database:        read/write

HyperHDR Server OS: 
- Distribution:   Ubuntu 21.10
- Architecture:   x86_64
- CPU Model:      Intel(R) Core(TM) i5-10500T CPU @ 2.30GHz
- CPU Type:       165
- Kernel:         linux (5.13.0-40-generic (WS: 64))
- Qt Version:     5.15.2
- Browser:        Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.54 Safari/537.36 

[awawa-dev]

No full logs