So in my new house of a few months I was going around testing all of the outlets to see they were wired correctly and checking the GFCI protection with an outlet cover. One of the GFCI outlets sparked and failed and I thought it was the outlet itself being old and I'd replace it. Went in to swap the wires where they started with the new outlet and found one of the neutrals still live. Further poking around I made this wiring diagram which is what it looks like is going on inside the outlet.

This to me seems very incorrect and my guess is was just a mistake by the previous owner's electrician maybe thinking that the line to breaker 17 was actually a breaker 15 line? My wonder is at this point I don't know what it is I should do to fix this? S/O would really like the outlets in the kitchen back (the 2 load lines) but I won't be turning it back on until I can understand that it's actually GFCI protected and wired correctly of course, just don't know what would be good practice to do to fix it.

Edit: noticed my diagram I didn't draw the ground to the GFCI outlet. The pigtail is screwed to the outlet yes.

Edit: Made a video to help explain issue with the outlet while the breaker 15 is pulled and there's still live wire in the box.