The way this works is this:
In one year (say 2017), you made excess contributions to your HSA. If your HSA contributions came through your employer (code W in box 12 of your W-2), then the excess amount was added back to Other Income on your 2017 return. Why? Because code W contributions are removed from Wages in boxes 1, 3, and 5 (this is why such contributions are not taxed), so the excess contributions which don't deserve to be tax-advantaged have to be added back to your income.
As I noted, this all happened on your 2017 return when you did it in early 2018.
Then, in early 2019, you received a 1099-SA with a distribution code of '2'. This tells TurboTax to add the amount of earnings in box 2 to your income on your 2018 return. If there is an amount in box 1 (likely the amout of the excess), it will be ignored, because it was already added back to income on the 2017 return.
The excess contribution will not affect the numbers on your W-2 for either 2017 or 2018.
