BryanDP,
From the way the manual reads. it is likely you have the mixer set up so that incoming and outgoing audio are combined. Whatever you hear is the same signal sent to the computer to be recorded. You need to split incoming and outgoing audio into two signals.
Page 7 details how the mixer usb port handles both audio coming into the mixer from the computer (receiving) and outgoing audio going from the mixer and into the computer (sending). Essentially it says you can send audio from the computer to two places (Ctrl or Main Out) but outgoing audio from the mixer to the computer is automatically sent to Main Out.
The mixer can send or receive audio to or from your computer through the USB connection.
• The main mix is sent from the mixer to your computer.
• Receiving audio is sent from your computer to the Main Mix Outputs
or Control Room Outputs (Ctrl Out), depending on the position of the mixer's USB
In Source button.(item 31 on page 6)
You want the received audio to go to the Control Room Outputs (Ctrl Out) because the outgoing audio must go to the Main Mix. You will use the "Phones Source" button (item 29 on page 6) to switch between the audio coming from the computer (Ctrl Out) and going from the mixer to the computer (Main Out) with raised listening to audio from the mixer to the computer (Main Out) and depressed listening to audio coming into the mixer from the computer (Ctrl Out).