when you completely dispose of an MLP all its suspended losses are allowed - that year and no other. if you disposed of an MLP prior to 2020, you didn't enter the information necessary to release those suspended losses. there wouldn't be a loss carryover to use in future years. In this case, I strongly recommend you seek the help of a professional because correct reporting, including any ordinary income recapture, can be quite complicated. Prior open year returns would need to be amended.
