The shed designer puts every 4 ft T1-11 panel joint on wood. Where an opening's king stud or cripples leave one panel edge bare, it adds a siding nailer, and if the gap is narrower than a stud it rips the nailer to fit. That ripping only looked at the member on the nailer's right.
The fuzz test's seed 7 found a 78" x 90" shed with a ridge beam. On its left gable wall, the post's two studs end at 43" and the king stud of a wide window starts at 44.3". The panel joint falls between them, so its left edge had nothing behind it. The nailer that should have filled the gap was 1-1/2" wide and overlapped the post. The tool threw it away rather than rip it to the 1.3" that was there.
The nailer is now trimmed to whichever member is beside it, left or right: here, a 1-5/16" strip between the post and the king. Both the framed and the floorless versions of the shed now pass the siding-joint check. The design is pinned in the tests, and the test fails without the fix.
The tool is a planning aid, not an engineered or code-checked design.