Bounce it down to audio temporarily (or better still, just freeze it) and play around with it

How are sending to the via send or output from track.

And of course, the compressor in the Master bus ProChannel is off...
 
I know you know to check that, but I'd be lying if I said I never overlooked something like that.
 
Regarding Offset, I have disabled the O shortcut key, but I used to accidentally set Offset mode without realizing it.  Before I mixed, I would have to go into Offset mode, make sure all faders were at 0, then exit Offset mode.
 
Still, offset mode on the track should still leave the track, bus, and master at the same level.  I actually don't know if there is an offset mode for Master.  If there is, I don't know why.

CJaysMusic

that bus is sending to the Master, and the volume peaks there. That's with all sliders and gain at 0. Should I expect volume to increase each time I send to a bus? Or should the volume at the bus be equal to track?

This is simple math. The sum of 20 tracks at equal volume is greater than the sum of 4 tracks at equal volume.
 
That means - The more tracks you have in a song, the lower each track fader needs to be or you will clip.
so if you have everything at 0dB ,you will be clipping when you add enough tracks and effects to the signal chain
 
Your Welcome,
CJ

CJ is correct, the summation of all the tracks and the buses are meeting at one location, the Master channel. Therefore, you can't have all of your tracks  level off at 0db and expect to have the Master buss, (the final dumping channel) to remain at 0db also.  Look at your Sonar's mixer, nNow imagine the volume of all your individual tracks adding up from left to right heading to your Master bus.  If you keep your channel faders close to zero surely your Master will go over 0dB and clip.  If you want to experiment, start a new project and just add one track and route it to you Master bus.  Whatever db you see on the single channel,  it will appear the same on the Master buss.  However, if you add another channel you be increasing the input to your Master bus and drive the total volume up higher.  Also the addition of plug ins add to the over all increase of Master bus.
 
In reality, when adding Multiple tracks in a mix, you should keep the channel faders set between -12db and -6db. Also, when adding a plugin, keep in mind that these plugins have volume input and volume output levels as well.  You must remember to turn down the track fader and adjust the plugin input or output volume levels to compensate for volume increase that will most likely occur by adding that plugin.
 
This is a good suggestion ~>  http://therecordingrevolution.com/2013/07/12/3-ways-to-create-more-headroom-in-your-mix/
 
Peace,
 
Jesse G. 

The OP is only talking about a single track

OK, I tested this.  I took the track that I had up at the moment and soloed the electric piano track.  I set it to 0 and set Master to 0.  There is no compression or effect on Master.  There are no sends.
 
In test 1, I routed the track through another bus before Master.  In test 2, I routed the track directly to Master.  In both cases, with the faders set to 0 db, the track and Master had identical peaks.
 
I repeated this with the snare track routed to the drum bus and then to Master, and I got the same results, meaning I could not recreate the problem.
 
I was hoping to find something for you, but I think there may be something subtle in your signal chain that is easy to overlook.  There are sneaky poltergeists out there who love to confuse us.

Thanks, it really slows down the process if people don't read the question carefully.

I'll keep looking, thanks.

Accidental send added from the track to the master bus?

Hi tindog13.
 
This Sounds like a case of missing the obvious.

tindog13
My sounds, a single snare for instance, at the track, never hits red, then I send it to a bus I've labeled "drums" and it cracks red at that bus, that bus is sending to the Master, and the volume peaks there.
 

This does not  mean that the snare couldn't be clipping at the gain pot.
some transients(e.g. snare) that are loud enough to clip just don't show up
on the track meters, many of which in certain DAWs have extra headroom
built in, in anticipation of the "hands on"(RTFM) user.
It is my experience that most problems with clipping occur at the input.
 

tindog13
Should I expect volume to increase each time I send to a bus?
 

In the case of ONE TRACK, as stated in the OP, the answer is no,
unless something  happened to the signal between input and the bus track meters.
 
m2c
Mel