Cue Point pad issue with DDJ SZ

Last night, I was DJing a party and half way through the night, all of the sudden, the cue pads on the right side of my DDJ SZ stopped working.  They still lit up properly, but pressing them did nothing.  Play and pause, moving the platter, everything else still worked fine. Just the pads stopped responding (note that I didn't think to see if other pad-related features worked like Roll or Samples).  However, when I switched the deck from controlling Deck 2 to Deck 4, they worked again.  It was only Deck 2 that made them stop responding.

This is the first time it's happened during a party but the second time in general.  It happened last week for the first time during a practice session, but I brushed it off, figuring it to be a one-time glitch.  Restarting Serato DJ fixed it.  But this time, I was in the middle of a party and obviously couldn't just close Serato.  Can someone help figure out why this is happening and how to avoid it again?