Boxes 18-20 have duplicate entries

Hi there! I'm trying to fill out my taxes using TurboTax. However, my W-2 has two sets of numbers in boxes 18-19 (a top number and a bottom number that are very different values) and the same locality number in box 20. I can't file the TurboTax without getting an error message that says, "We need to fix an error with boxes 18-20

Here's what to do:
  • Check the following entries against your W-2 and delete the duplicates using the trash icon. Each box 20 locality should only appear once.
  • Make sure the remaining info for boxes 18, 19, and 20 match your W-2."

How can I fix this? A friend suggested that I add the values of each number and place them in once, but I'm not sure if that's okay to do.