I started a project, created a drum clip and essentially just copied and pasted. For some reason, when I get to one specific measure, the drums are suddenly much quieter than the other drum clips. It's only that track that has a volume difference. I re-copied and pasted, tried different clips but the same result.  What would account for the sudden volume change on that one track? I even just dragged the drum clips forward to create a loop but the volume stays lowered at the same measure.
 
Any help is appreciated.

Is it only that one bar on that track?
 
Stab in the dark, but is there any automation on that track?

No, I also notice that the track slider is set to the same volume for the normal tracks and the quieter tracks. I can't even seem to create a new clip without it being quieter on that track...

Can you see an automation envelope - in clips pane is there a horizontal line running along the track, which dips in the problem bar?
 
Disable automation read on the track by pressing the "R" button in the track pane - does this still persist?

What sort of track - audio, MIDI or SIT?
 

Popping out for a min now, but have you checked input gain on track?  Offset mode - is there a little "+" sign that isn't on the other tracks?
  Press "O" to toggle it on and off.

No automation line dip at the problem bar, what I did was delete all of the clips and just created a new instance at the beginning, dragged and they are all now the same volume...I was just thinking back though (because this was an old project revisited) and I may have had different driver settings when I initially created the track, though I wouldn't think only one track would be affected.

I might be able able to help Doc
I had this with punch ins in a bass track.  but i basically had the same problem.  The track played fine up to the clip and then volume dropped.  Here is what cakewalk supporta advised and it worked.  In the left hand pane of your track view (for that drum track) you will see an item called Clips and a drop down arrow beside it.  Clips is the default heading.             Click the drop down and there is an item called Clip automation with two sub items called Gain and Pan.     Chose Gain.   You will now see a red line running horizontally across that track.  this red line can be dragged up and down vertically INDEPENDENTLY at each clip.  So you can adjust the gain of separate clips of the track as opposed to adjusting the whole track.  Im not sure if its possible to send screen shots in the forum but i'll send some if anyone can advise how i do it.  Cheers
Xave.