Check out row number 5,517 in your output file (I find it easy to highlight the row so it's easy to refer to) - this is the last recording where the Mach selector is at M0.8 (shown in column PX - FCC1MachSel). After that row was written, the mach selector was changed to M0.68 and the rest is history! The engine speed was reduced and the actual speed bled off until the autopilot couldn't hold altitude anymore and was disengaged.
It also looks like you were slowly climbing to reach FL370 maybe in FLC mode? When the mach selector was changed from .8 to .68, your vertical speed jumped up to 3700 fpm in the climb before the airplane leveled and speed continued to bleed.
I'm not sure why the mach speed selector would have changed without your input, but that would be the root cause of the crash.