I had the same problem - a rental property that does pass-through taxation to my wife and me, and the error check of TurboTax Business coming up with missing info for Schedule K, Line 20, Code Z, which just said “STMT”. I eventually solved it this way:
(1) clicking “Forms” at upper right in TurboTax to enter Forms Mode,
(2) opening each Schedule K,
(3) finding Schedule K's line 20 information (with the Z entry) and below that some text “QuickZoom to enter Code Z Section 199A information” and clicking that QuickZoom button,
(4) scrolling down because the place it jumps to (Section D1, Qualified Business Income Deduction – Statement A Information) is placed at the very BOTTOM of the screen, and
(5) entering the Ordinary Business Income and Rental Income from the Schedule K's (even though these were entered elsewhere), and entering 0 for Section 199A Dividends.
This seemed to satisfy the error checker in TurboTax Business.
