My club uses a CDJ 900 nexus setup that works fine, untill tonight. One player had major issues with the buttons at the top and responding on the display. Especially the back button, menu and info. A random menu would come up, browsing or sorting (into bpm) would result in the default menu for artist, playlist, history etc. Even when not touching the buttons the menu's would switch. Problem persist after shutting down / restarting, and with different usb sticks. (Also both direct usb and via link.) The usb sticks work fine in other clubs with other cdj's. I had no cd's to test. Both players have firmware 1.31 (= current).
The sticks were last synchronised today with Rekordbox 5.8.0 (= current) on Mac OS 10.14.6 Mojave (all updates within 10.14.6)
I made some video's that hopefully visualise the problem: