We have found a mistake in power flow normalization in Ref. [1]. The correct values of power flow S for given nonlinear coefficient α are 4 × 10⁶ times larger than those presented in [1]. Thus, the values of the energy flow on Figs. 2,4,5 and the values of power flow provided in the text should be multiplied by 4 × 10⁶ in order to obtain correct values. For example, on the Fig. 2 the correct maximum value of symmetric mode energy flow is S ≃ 24kW/m at β ~ 17 and symmetry breaking is observed for S ≃ 20kW/m at β ~ 16. The bifurcation on Fig. 5 appears at S ≃ 4kW/m.

We thank Matteo Conforti for noticing the descrepancy.