This sounds very similar to the fix for a double shift. Sometimes the switch under the button[paddle/shifter] goes bad and records two shifts for each push on the button, very bad.
The fix for that is to use the Logitech Profiler. First a letter on the keyboard is selected as the button for shifting, the switch used for shifting on the wheel is then edited so it selects the letter with a press with a .3 second delay before the release.