How does TurboTax calculate "forfeited" dependent care benefits?

In 2019 but I contributed $5000 pre-tax to a Dependent Care FSA. Because my wife didn't work in 2019, I believe that Form 2441 should show a taxable benefit of $5000. Instead, it only shows $700 because TurboTax says that we "forfeited" $4300 (as indicated on line 14). It's not clear how TurboTax came up with this number. In reality, we ended up getting reimbursed for nearly the full $5000.

 

Has anyone else had a similar experience with TurboTax generating seemingly random "forfeitures"?

 

(FYI, all numbers have been rounded to the nearest 100).