Spent three hours chasing a weird noise that turned out to be a zip tie

I was running a job on our old Haas VF2 yesterday, a simple aluminum bracket, and about halfway through I start hearing this faint, high-pitched buzzing sound. It wasn't the spindle or the coolant pump, it was something else. I mean, I shut everything down, checked all the way covers, the cable carriers, even pulled the way covers back thinking maybe a chip got stuck somewhere. My lead hand came over and we both just stood there listening, poking around for like an hour. Finally, I'm laying on the floor with a flashlight and I spot it. A single, leftover black zip tie from some old wiring was dangling just enough to tap against the sheet metal cabinet door with every tiny vibration from the machine. Snapped it off and the noise was gone. Has anyone else ever lost a huge chunk of time to something that dumb?