If turbo tx deducted my 3000 capital loss in 2018 and also deducted the same 3000.00 capital loss again on my 2019 return is that correct?

[Critter]

Ok ... look at the 2018 return ... on the 1040 there may have been -3000 but was it really used ?   The cap loss cannot create or add to an NOL so it is possible that it really wasn't used ... again review all the forms AND worksheets to what happened. 

[Bill-A1]

It was used in 18 and 19 but the 25700 standard deduction was more than total income before social security 

[Critter]

And voila ... if you read the carryover worksheet this fact would be obvious ... when the loss cannot be used it is carried forward in whole ... one of the nicer rules.