There appears to be a bug with code snippets.. Both in the released version and the developmental version.
If you create a part file with a code snippet under cutting operations. Then later try to remove the code snippet by selecting "None" on the Cutting operations screen. It does not remove the code snippet from the part.
It will show up as "None" in the cutting operation. But when posting it the code snippet will show up in the gcode
I have run into the same problem. I understand it staying with the tool library, but it seems to stay there even if you only put it in the operation for a specific job.
You have a snippet assigned to your start point. Switch to start point mode, right-click on the start point and select 'properties'. You need to disable the snippet in there.