I think there may be a glitch in Turbotax form 2441, Dependent Care Credit? If you start this turbotax form BEFORE both parents' W-2s are filled out, I think it assumes someone isn't working, won't ask you for your daycare expenses (it keeps asking if either of you are disabled or a full time student instead), and will thus make your FSA contributions taxable? And it didn't self-correct when the other W-2 is eventually entered. So once BOTH W-2s are entered, try deleting any previous form 2441 (see below), and re-enter the Dependent Care Section (form 2441) questions again. It then FINALLY asked me for my daycare expenses and worked fine!
https://ttlc.intuit.com/turbotax-support/en-us/help-article/small-business-processes/delete-form-244...
