IWR6843: 3D People Counting cannot restart with new config

This happens with both the IWR6843ISK and the IWR6843AOPEVM.

The mmwave sensors are flashed with firmware from the People Counting lab (68xx_3D_people_counting for the ISK and overhead_3d_people_counting for the AOPEVM). I will focus on the AOP for rest of the post, but it happens with both modules.

1. Send a valid chirp config to over the USB command UART. (with the AOP, we use pc_6843_3d_aop_overhead_3m_radial.cfg)
   
2. Once 'sensorStart' is sent, the data UART starts sending data
3. Send 'sensorStop'. The data UART stops sending data
4. Optionally, send 'sensorStart 0', and the data UART resumes sending data. Send 'sensorStop' again to stop it.
5. Resend the same chirp config as before.
6. The command UART confirms each command, except the last one: 'sensorStart'
7. The module now no longer responds to UART commands, and needs to be power cycled

Versions:

mmwave industrial toolbox 4.8.0

mmwave sdk 3.5.0.4