Default [Q] Strange issue with USB OTG

The problem I'm facing is this: out of the blue, my device has stopped recognizing the USB OTG, even though it is detected!

So, the N7 is rooted and I'm using stickmount, which detects the usb as normal when it is plugged in, assigns it a name and everything, but when you open the folder in ES explorer (or any similar app) it is empty!

It is not ROM related, because not only have a tried a few different ROMs, but it is also not recognized at all by TWRP.

Also, keep in mind that: a) it used to work perfectly well, and b) it works fine on my N5!

Any ideas? I've searched high and low for a solution to this, but have so far been unable to find anything, so any ideas or input would be vastly appreciated!

Alex