Excess Roth IRA contribution made in 2018 lost value and amount withdrawn was less than contribution amount. Turbotax incorrectly adds the difference as contribution!

[dmertz · Accepted solution]

When TurboTax asked how much of your contribution you had returned, you likely mistakenly entered the loss-adjusted amount distributed instead of entering the unadjusted amount of contribution returned.  If the excess was, say, $500, and account lost 10% so the adjusted amount distributed was $450, you must indicate that you had $500 returned.