XDJ 700 issues with beatmatching

When using my XDJ 700's it so happens that I'd beatmatch two tracks, they will remain beatmatched for a few seconds and then start to drift slightly over time. I am using high quality tracks so don't think it's a file format problem.
Using my friend's XDJ-RX2 or my old DDJ-400, I noticed that I can keep the 2 tracks beatmatched for many minutes without they start to drift over time.
Searching on internet I read that also other people have my same problem using the XDJ-700.

So I gently ask if there's a way to solve this problem or if Pioneer will release a new firmware.

Thank you very much