DDJ-RZX : Music hesitation using rekordbox

Played at Wedding this past Saturday using the DDJRZX
When mixing some music was dragging. Seems as a buffing
Error. Trying to catch up. Also my Master tempo was not letting me adjust
Manually. Been through settings, I can't figure it out. I run I7 turbo 16gbram
Mac Pro Retina can't be that! Someone help me understand ??