Willams2 explained how to fix this problem, but it's important to know how to prevent it in JWM.
First instance simply plugging in a USB creates a 2nd pinboard. The partition icon blinks on and off clicking on the desktop. Second instance when you want to refresh drive icons in the Puppy Event Manager, a second pinboard is created with the same fix (killall ROX-Filer, restart PuppyPin).
How do we prevent 2nd pinboard creation in the first place?
currently in 64 Xenial