Each opening in wall-framing-takeoff gets jacks and king studs on both sides. When two windows sat close, their kings landed on the same spot and the engine refused the wall.
Framers handle that by sharing: one king between the two sets of jacks. The engine now does the same when the gap is at least jack + king + jack (4.5 in with the usual one jack and one king). The shared stud is labelled in the cut list, and any sliver left over is noted so you can block it. Closer than 4.5 in is still refused, but the message gives the gap and the minimum, and suggests drawing one wider opening instead.
Checked against hand-computed stud positions and the per-wall self-check, not against a framer's real wall. Estimates only, not engineering or building-code advice.