DDJ-400 Release FX stuck on occasionally when using shift + on/ff

Just got the 400 and enjoying the performance pads, but it seems that very occasionally the release fx activated by shift + on/off(fx) gets stuck on? I can see in the software in rekordbox it's still turned on so the track keeps playing, but no sound as the fx thinks I'm still holding the button combo down, but I have released it. I can get it playing again by pressing shift + on/off again to release it, but that means any recording will be messed up?

I have no issue with the fx on/off button without the shift combo so want to know what's going on? My guess is it's a software issue as I have no problems with the buttons on the controller apart from that?

Is this a known issue? Will it be fixed?

Thanks

Rob Shillito