I have the same issue. Trying to use DeMinimis safe harbor method. TurboTax does not do Form 4684 correctly. Rev Proc 2018-08 requires leaving lines 5&6 blank and entering loss on line 7. IRS requires a statement attached to return which TurboTax does not generate. Only way out is to override Form 4684 and manually prepare a statement and then mail in return.
