This is a guess....but you are probably playing a different course (with a different slope) in each event and have set League Manager to adjust the golfer's handicaps according to slope of course being played.

Final Handicap = Handicap x (Course Slope / 113)

See bottom of a golfer's "HOW IS HANDICAP BEING CALCULATED" report to see if this is being used for the golfer in question.

To set the option....to NOT use Slope in final calculation:

1. Pull down the SETUP menu and select Handicap Calculation Parameters

2. CHECK the option "Do NOT use Home Course slope in final calculation"

Note: Usually you want the slope used...this is the reason the USGA (United States Golf Association) slopes courses.