gmoccapy z height after hitting start

Understand. I use freecad to generate the gcode from 3d models. The gcode header seems to be the same. I compared a file that was causing the issue with one from 2 years ago. Only the date and tool size was different until after the G43 H2 line which prompts for inserting tool 2.
This is routine as I always create a different path job for each tool so they are always tool 2 ( 1 being the default tool).
Why did the behaviour change?

tool size was different until after the G43 H2 line which prompts for inserting tool 2.

That command does NOT prompt for 'inserting tool 2', that command activates TLO with offset values defined in the tool table for tool #2.

If you are not using TLO in linuxcnc anyway then I would recommend setting freecad up so it does not output GCODE that activates TLO. This way there are no surprises whatever offset values you have in your tooltable.

Why did the behaviour change?

Probably not the answer you want but most likely due to operator error.