TUX 99% Usage when using a module

Hello!
We are testing TUX using a custom module.
Every now and then tux will go to 99% usage and stay there until one of two things happen...

This only happens when using our module.....

(1) Hit the cancel button on the browser that is making the request
    then tux returns to normal.

(2) Bring up another browser and make a new request.
    then both browsers complete as they should and tux returns to normal.

Can someone give me a hint on what to look for that could cause this?