DDJ-SB3 Headphone Master Audio Volume Fluctuating + Flashing Rewind LED

Hey guys,

Today i started mixing and decided to do it using my headphones and the master as my housemates were asleep; however, when mixing I am noticing that the music will fluctuate in volume (getting alot quieter) and whenever it gets quieter the rewind LED will start flashing. I've tried updating my firmware and this doesnt happen when mixing with the Master Level.

Anyone have this issue?