**Appendix C. Mode-Coupling Instability Oscillator with Isolated Solutions**

Compared to the system configuration given in Appendix B, the damping parameter values are set to *d*<sup>x</sup> = *d*<sup>y</sup> = *d*<sup>z</sup> = *d*lin = 0.002. Initial values on the periodic orbits at *k*<sup>x</sup> = 11 for the weakly damped system configuration read

$$\begin{array}{cccc} \mathbf{y}\_0 = \begin{bmatrix} -1.1366 & -4.5527 & -1.2077 & -0.0125 & 0.0722 & -0.0054 \end{bmatrix}^\top & \text{LC1} \\ \mathbf{y}\_0 = \begin{bmatrix} 5.9650 & -6.6938 & -4.5901 & 0.2163 & 8.6960 & -6.1122 \end{bmatrix}^\top & \text{LC2} \\ \end{array} \tag{A3}$$
