If I entered the $4100 I earned during a seasonal contract into Box 48, why does does that amount get doubled in my income summary?

Enter the amount only once in Box 48 on the T4A screen. Choose either Business or Professional fees which ever is applicable. Then complete the corresponding schedule under "Income" > "Self-employment" to arrive at the correct taxable income.

Thanks but I have only entered the $4100 in the one box (48) on the whole return. It doubled itself so when added to my other T-4 (non-self employed) income, my total income shows as $4100 more than I actually made. I'd really like to know why. I haven't completed the T2125 yet, but I don't think that addresses the doubled income entry issue.