Used DJM-REC to record my set but lost the last 20 minutes after finishing it

Hi Guys

Just wondering if there's anyone had the same problem and how to solve it?

Me and the other DJ were recording our b2b set using DJM-REC for 1hr10mins. It was all fine but after I stopped the recording I found that my file is only 47mins long which is weird because I am sure it recorded the whole set!

The mixer we were using are DJM900nx2. Has anyone had the same problem? Thanks!