DJ says it's recording but stops recording even though it appears to be recording.

Have been using dj for about two years with no problem. I primarily use auto mix for hour long playlists. This just started to occur. I will be recording the mix as usual and it appears to be recording properly. Timer says the recording is the proper length, say one hour but then when I stop recording it appears in the list in a truncated fashion. For instance it will be 5 minutes, 13 minutes, etc. When I export to iTunes it starts the play list at it’s proper point but then indeed stop at 5 minutes , 13 etc. Any ideas?