I would bet on the neighbors overspray drifting over. I had that happen a couple years ago, and that was the only thing I could come up with. The next door neighbor was spraying roundup on weeds in the fence row one evening. My brugs were probably 15 ft away with a few other plants. All the plants ones closest to the fence had leaves the next day that looked just like your picture. One plant died, but the others came thru it and regrew leaves again. I moved everything on that side of the house!!!
