I think I discovered a bug in TurboTax.
This year, because I switched jobs, I had an overpayment of Social Security Tax (exceeded the $7,886.40 cap). However, when I enter my W2's in TurboTax, it properly assigns those W2's to me, and shows up as a surplus in line 4 of my W2/W2G Summary. However, the calculation for line 71 is zero.
I tried starting over with a new file to see if I messed up something on the W2 entry or import. I tried this a couple times. I found that when I imported my prior year turbotax return information, THEN the calculation for line 71 is in error. But if I create a new turbotax file with NO import from prior year, then the calculation is done correctly.
Bottom line, if you are a prior user of TurboTax and know you overpaid your SS taxes, DONT trust Turbotax to "automatically do this calculation for you". Double-check line 71 of your 1040 to make sure your Social Security tax overpayment is properly reflected.
