Music stops for one second on MacBook

Hello everybody,
I use djay Pro on a MacBook Pro (Mid 2012, Yosemite) for 2 months now and the past 2 weeks I have the following problem.
Once per night, the deck that is playing increases the song speed, does a small fast forward and music stops for one second. Then everything goes back to normal.
There is no specific pattern that causes the problem. Has anyone something similar?

edit: I am using Reloop Beatmix