Where exactly are you looking at an OMB number in TurboTax? There is an OMB number at the top of the Form 1040, 1040A, or 1040EZ, and some of the other tax forms, but those have nothing to do with your W-2. They're not supposed to be the same. There is a different OMB number for each type of form.

The OMB number doesn't matter. Don't worry about it. There is nothing to fix.