the “mix pulse” function of the Pioneer DDJ-Ergo V controller isn’t supported in Djay yet. Please add this in a further version of Djay. In Virtual DJ it works fine and it is very useful.
This is the description on the Pioneer website:
A blue LED on the jog wheel shows how close the phase of the mix is during a mix. The bigger the difference in pitch, the weaker the light. The closer the match, the more intense the light shines."