Once in a while, when using my XDJ-RX2 with USB drives and not connected to a laptop with rekordbox, I discover I am unable to use the Delete and Memory Cue buttons on tracks to set new memory cue points or delete existing ones; the bug does not simply disappear when a new track is loaded, and will occur on both decks. The Cue/Loop Call arrow buttons still work properly to jump between memory cue points, so it's not like the memory cue function itself is completely nonfunctional. The issue often disappears when I disconnect and reconnect my USB drive, but there have been a few times when the problem did not immediately disappear and required another reconnect.
Unfortunately this issue occurs infrequently so I have not been able to determine what factors allow me to replicate the situation, and my tendency to only use the USB 1 port means I am unsure if the problem can occur on both ports.
Is this likely an issue with the RX2 firmware, the USB port, or the drive being used? Is there a setting I can verify in rekordbox that could affect how the drive is set up, or any other tests I should try to get the issue to come back?