Bought new. Often the fader will snap to closed consistently when going back and forth a few times, not sure how to fix it. Other controllers on the software not having this issue, must be something with the bluetooth connection or djay app? Here’s a public video of the issue: Pioneer DDJ-200 Crossfader Issue with DJAY iPad app - YouTube
running on iPad Air 3rd Generation and latest Djay 4.0.9. but the issue happens on my older iPad, iPhone XR too, so not sure it’s a device issue. Also had this issue for a few versions of DJay.