There could be a couple of reason that it doubled:
I suggest you review your Income --> Tslip section and click Modify on the right side of each slip to review the information entered or Delete to delete a slip entered by mistake.
Each time you use Auto-Fill My Return, TurboTax will download everything available. TurboTax will summarize what's available to import into your return and you can choose to import it in or not, slip by slip. In other words, you can't pick and choose boxes, but you can pick and choose which slips to import.
That being said, TurboTax won't duplicate the slips you've already downloaded and imported if you import again, so long as you didn't significantly change the amounts of the slips you already imported. TurboTax will recognize that you already imported those slips.
Please do let me know if the information above helped you. If not, can you please explain further what doubled specifically?
Thank you for choosing TurboTax.