Shoutout to the panel that took me 9 hours because of one stuck zone

Last Tuesday I was finishing a takeover job in a 1970s split level in Naperville, and one zone kept reading trouble no matter what I did. I swapped the reed switch, re-stripped the wire at the can, even ran a jumper straight to the panel terminals. Still open. I spent about 3 hours chasing it with my meter before I finally crawled back into the attic and found a tiny nick in the jacket where a staple had rubbed through against a joist. The copper was touching wood but not shorting, so it read as a high resistance fault at random times. Total time on that one zone was 9 hours across two trips, and the fix took 4 minutes with a piece of heat shrink and a new staple. I felt like an idiot but also relieved it was not the panel. Has anyone else had a staple rub cause an intermittent open that only shows up when it is humid?