CDJ 2000 NEXUS QUESTIONS

hello, i just upgraded to the cdj 2000 nexus players, and have a few questions for the pros. 

1. is there something i can do to prevent in "vinyl mode" when i back the track up to far, it switches into the previous track in the list in my folder. its kind of annoying. my old 2000s it would never go into the previous tracks.

2. kind of a rekordbox question. how come when i analyze tracks, some do not produce waveforms??

thanks in advance

brandon