First of all, QML debugging is done in the wrong syntax. First, prepare any Qt Quick project (literally any so any of our examples and even a boilerplate will do - and I am not providing a specific reproducer here), build, and debug it. The debug command goes like:

Starting pdebug 10000 "-qmljsdebugger=port:10001,block,services:DebugMessages,QmlDebugger,V8Debugger,QmlInspector,DebugTranslation" on QNX Device i.MX8...

None of the arguments passed to pdebug (other than port number) is valid. Pdebug only recognizes those arguments:
https://www.qnx.com/developers/docs/7.1/#com.qnx.doc.neutrino.utilities/topic/p/pdebug.html
And somehow those QML debugging ones get into pdebug side.

Next step, disable QML debugging from "Build and Run -> Run", and retry debugging. This time, all weird arguments are gone and only port number is passed to pdebug. But still debugging does not work.

Like, breakpoint is set but not respected. No information comes to QtC anyway. No logs, no local variables, nothing.

Finally, a minor issue is that force stopping debugging from QtC side (click the red square button) doesn't seem to actually stop debugging. If you check what are being run on QNX device, you'd see multiple pdebug processes like

# ps
       PID TTY          TIME CMD
     90146 ?        00:00:00 ksh
    118822 ?        00:00:00 sshd
    135209 ?        00:00:00 resarb
    294957 ?        00:00:00 sshd
    192558 ?        00:00:00 ksh
    200751 ?        00:00:00 inetd
    303152 ?        00:00:00 sh
    307249 ?        00:00:00 sh
    340018 ?        00:00:00 sh
    364595 ?        00:00:00 sh
    385076 ?        00:00:00 sh
    385077 ?        00:00:00 sh
   7335990 ?        00:00:00 ps
   1310778 ?        00:00:00 pdebug
   4689979 ?        00:00:00 pdebug

Obviously they are leftovers from failed debug session.