Same here, so here's what worked for me.
Go to the forms view (on the view pulldown select Forms)
Find your K-1s in the list of forms, they will have a (Not Done) note on them
Select one.
Scroll down to near bottom of page 2.
You'll see a RED Z under code 20 section.
Double click on the QuickZoom button to the right of where it says **QuickZoom to enter Code Z Section 199A information.
Find the K-1 you are working on in the Open Form pop up box that appears, select it and then select Open Form at the bottom.
I had a value that should be in Passive Income and Loss so after I entered it there, the error went away and so did the (Not Done) note.
Hope your issue is similar.
