A good place to start looking at your routing is in console view... A "master" bus is just like any other bus. Signal(s) are purposely routed there for summing / processing. As mentioned above, the master bus is usually purposely routed to the soundcard outputs by the user.

To summarize:

• The Bus labeled "Master" is the master output to your audio interface, not the master mix bus.
• The Normal template creates a master bus for mixdown. If it's not there, you will need to create one and send your channels to that master mix bus.
• Some plug-ins, particularly dynamics processors, have a function called "look-ahead." This allows them to "predict" transients and act accordingly. Sometimes toggling the PDC button will help. However, I use processors with look-head only for mixdown, not tracking.

Anderton
To summarize:

• The Bus labeled "Master" is the master output to your audio interface, not the master mix bus.
• The Normal template creates a master bus for mixdown. If it's not there, you will need to create one and send your channels to that master mix bus.
• Some plug-ins, particularly dynamics processors, have a function called "look-ahead." This allows them to "predict" transients and act accordingly. Sometimes toggling the PDC button will help. However, I use processors with look-head only for mixdown, not tracking.

Thanks for all of the help!

Just for the sake of clarification, there are Audio & MIDI Track strips, Bus strips and Master/mains output strips.  These are all divided into sections across the Console View.  The mains outputs strips (eg. channeled to monitors/speakers, headphones, etc., depending on how many outputs your soundcard has and the number of those outputs checked in Preferences) do not have an FX bin or PC processing.
 
Kind regards,
 
Living Room Rocker
 
P.S.  At times the words "channel," "strip" and "signal" may be used interchangeably, but they are specific to parts of a studio setup.  That is, a signal is the actual sound or electric "signal" traveling through cables, for instance; a strip identifies the section of controls designated to a specific track or bus on a console; and a channel is the route the signal takes in, through and out of the studio setup.
 
Just saying.

Another good way to see this is that:
 
-Tracks have a black fader
-Busses have a blue fader
-Mains have a fader
 
This is the case if you you don't use a mod to change the color of your faders for tracks, busses, and mains.
 
Tracks and Busses have an FX Bin, but the Mains do not.