Amplitude of oscillations in mutual planet–planet inclinations excited between two initially coplanar, circular planetary orbits βrel, scaled by twice the stellar obliquity β⋆. The planets are situated at 0.05 and 0.1 au for three different mass configurations: the red line has a 10 Earth-mass planet outside a 1 Earth-mass planet, where blue has the planets switched. The cyan line augments the inner planet to 100 Earth masses. Notice that any time the inner planet has more angular momentum, there exists a peak in the misalignments, representing resonance. In the limit of large J2, the planets entirely decouple and reach mutual inclinations equal to twice the stellar obliquity.