Pennsylvania Box 18 - Local wages & tips,Box 19 - Local income tax, Box 20 - Locality name 21 - These are being called duplicate errors. Boxes 18-20. They are not!

The entry in W-2, Box 20, is the name of the locality responsible for assessing your local income tax in Box 19. It could be a city, town, school district, or something else. 

Depending on where you live, you may even have more than one locality. If you do, just add a new row to enter info for another locality. Click on "+Add another locality" and TurboTax will add another row of entry boxes. You can add several rows if you have several different localities.

There should only be one Box 20 entry per locality. Check with your employer to determine whether one of the duplicate localities is incorrect. All of the wages taxed by one locality on one W-2 should be on a single line on the W-2.