OK, I just ran this and it did work, thank you, and I see now the multiple layers/depths was just my novice lack of understanding.
BUT this still doesn't show where the astronomical -Z values were coming from...I can assure you I never typed in -Z in the thousands!! LOL ...
(I did notice in the G-code the bad line was the only -Z value that was NOT preceded by a G!....that must mean something...?)
PS - I am assuming u let Lcam decide the cut order of the chains?
I see yor file also adds a LOT travel for the bit that is completely unnecessary like mine does ...doing it manualy sucks But it's either more time on that, or more time for the actual cutting.