Scalar signatures for the case VA3, where a secondary KH instability has set in. Plotted are the maxima of (a) u and (b) B_x (solid line) and the modulus of the minimum of B_x (dashed line). Alternating magnetic structures still emerge after the instabilities have set in, and the background shear is still affected, but in a somewhat different manner than for the pure shear‐buoyant instability.