Hi RLO,
In my case, I was able to file Form 8978 with my 2019 return. Form 8978 allowed me to amend 2018 taxes without having to file a 1040-X.
I also found out that the IRS does not accept e-filed returns with Form 8978, so I was forced to mail it in. It took a little over 3 months for me to receive my refund.
Good luck!
