I also had the exact same issue of loss carryover from 2018 (and prior years) not transfer into 2019, for both kids tax returns. I believe this is a bug for sure. (how do you report a bug to Intuit?)
How I got around this problem was start from scratch, after transferring personal data, DO NOT IMPORT anything else yet (brokerage accounts, W-2 whatever), which is one of the first prompts if you walk through the Wages & Income section. Instead, jump to the "Investment Income" section within Wages & Income, update the Capital Loss Carryover first. That way its in your 2019 tax return, THEN import whatever documents, like brokerage, bank statements etc. Everything worked like a charm then.
