I’m confused on your split. You said you split at 909013?
But the second file starts with:
Line 909015 matches your start point in the other file (line 14), but that arc in question is well before that in the original file (line 909000).
I’m halfway through your file from the grbl post (past the error you had there) and it’s checking out. I have a feeling that if I checked your original file, it would check out as well. The problem looks to be in the manual split.
That’s a rough cut/paste to handle with a text file that big. Maybe you could split the job in fusion and export separately.
You’re cutting a max depth of one inch. Start the first operation with a Top Height at the top of your stock and the Bottom Height at 1/2" down. The next operation would start at 1/2" down and finish at full depth. Post each op separately.
P.S. I’ll let you know tomorrow (today, I guess, but later) if the file checks without errors.