Aux track no longer responds to signals sent to it. [SOLVED]

Inserted an Aux track and then pointed two guitar tracks to it. It seemed to work fine. I could control the level of the guitar tracks from the new Aux track and the meter on the aux track responded as expected. Now after some hours the Aux track no longer responds yet I can hear the two guitar tracks pointed at it. The meter no longer responds nor does the fader make any difference to the level.
 
The output of the guitar tracks is sent to the aux track which then outputs to the main buss. It is my understanding that the aux track should function the same as if it was buss, in the buss section. It did work that way when I set it up, but now appears to do nothing. What have I missed?
 
Cheers
Wal
 

Did you arm the aux track for recording? In that case you'd be metering the input instead of the output, so the metered level wouldn't change with Volume but the audible output level still would. I can't think what would cause loss of output level control unless maybe you've got a Prefader Send going somewhere; even then, you'd hear some change in level.
 
Or possibly the sends are on the guitar tracks, and you've inadvertently disabled Input Echo on the aux track as Klaus suggested so you lost the aux contribution, but you're still hearing the sends...?
 
Or it's a bonafide bug that has allowed the track to get into a bad state, in which case you might need to recreate it or at least replace the patch point.