Chain slipping off from singlespeed rear cog
Campag toolboxes used to have a tool, looked like a satin chromed steel bar, that was to be placed on the right side of the BB and swung to the left inside of the right frame end. If it didn't just brush nicely, the stays were out of whack. Triple check your BB/cog alignment. All need to be in plane. An aligned chain wheel can't ship the chain off an aligned cog. Determine plane.