Curtain Rod Electrified?

I installed a metal curtain rod on a wall, and on the exterior side of this wall there is an outdoor lamp (line voltage). I felt an unusual resistance when drilling into the stud, but didn’t think much of it (could be a knot). On the back of my mind I wondered if I had screwed through a plate and hit the lamp wire (it runs in the same direction as the rod, just not sure where exactly). Went back with my no-contact voltage detector and the thing started beeping like crazy when held to the metal rod, metal brackets or some of the screws, and only when the lamp is switched on! This put me on high alert. Came back with a multimeter and touched various parts of the rod/brackets/screws with the red probe, while the black probe was grounded into a power cord (itself plugged into a nearby outlet). It actually registered 1 volt in some places, whether the light was on or off. Not sure what that’s about, but definitely not 120 volts. BTW I tested my contraption (multimeter grounded through a power cord) so I’m confident that was working. I can’t bring myself to voluntarily touch this rod…