Oh wow - so it’s completely ignoring any characters it doesn’t understand and trying to run everything else as “valid” gcode. That is scary.
No worries. Python is a scripting language. There would be other options in this case, it’s just what I’m used to - unfortunately, unlike Mac OS and Linux, Windows doesn’t really have any decent built in scripting options but you can install python.
Basically, download and install this: https://www.python.org/ftp/python/3.9.1/python-3.9.1-amd64.exe
And then you can run python scripts from the windows
With this hypothetical post-processing script you would save the gcode file locally and then run:
python smc5_post.py laserjob.gcode
The script would then strip out the comment lines that are causing you trouble and you would then send that file to your controller.
Granted, this is all hypothetical. I have no idea if your controller would have other problems with that LightBurn emits.
If you think you would be up for running a python script as described, I’ll send you one that does that. Under normal circumstances we definitely don’t do custom script programming for customers, but this is so little actual code that it would take me 1 minute to write. And I’m just curious.