Thank you for your question.
There are a couple of reasons why this could happen. For example, some income on the T4A is considered to be self-employment income, such as amounts in Box 20, Box 48 and Box 28.
When you enter a T4A with one of those amounts, and then create a T2125 - Business Statement, TurboTax will automatically add the amounts from the T4A to that form. So if you include the amounts from your T4A in your "Sales, commissions, or fees" or "Other Income" amounts, it will be doubled.
Other times, you could've manually put the same amount in 2 separate places, and have forgotten about it.
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