CDJ-2000 freezing after an hour (or so) of playing

I've run into this problem a number of times now, but only when I seem to play with my CDJs.

Set-up details:
2x CDJ 2000 (linked to traktor 2.10.0 HID Advanced)
DJM-900 Nexus mixer
Traktor Kontrol X1 MK2
USB hub
Toshiba Satellite Laptop/Windows 8 64-bit

This occurs when I hook up my CDJ 2000's to Traktor (2.10.0) to play.  After about an hour (give or take, sometimes more), the audio will just stop, and the waveforms in traktor will freeze.  I still have full control on the CDJs, can scroll through the menus and folders, but I cannot load a new track.  Traktor tells me to stop the track before loading a new one (as it thinks the track is still playing), but with the waveforms frozen, there is nothing I can do.  Re-starting the CDJ and re-linking it doesn't make any changes.

Traktor itself is not frozen, as I can adjust knobs on the screen, but I cannot load/unload the track or get any further playback.  It requires a restart of traktor.

I do not have this problem when mixing with just my X1 on the 900, it only seems to occur when I use the CDJS.  The CDJS are hooked up via usb to a usb hub, my mixer and the x1 are both hooked up to usb ports on my laptop.

I'm sorry if this is a repeat topic, but I've had trouble finding anything specifically related to this type of issue.

Firmware on my CDJs is 4.33 and the 900 firmware is also up to date.

Any suggestions/help would be greatly appreciated.  Thank you.