Comment on Sequential Single-Pion Production Explaining the Dibaryon $d^*(2380)$ Peak

In arxiv: 2102.05575 a two-step process $pn to (pp) pi^- to (Delta N) pi^- to (d pi^+) pi^-$ was calculated by using experimental total cross sections for the single-pion production processes $pn to pp pi^-(I=0)$ and $pp to d pi^+$. As a result the authors obtain a resonance-like structure for the total $pn to dpi^+pi^-$ cross section of about the right size and width of the observed $d^*(2380)$ peak at an energy about 40 MeV below the $d^*(2380)$ mass. We object both the results of the sequential process calculation and its presentation as an alternative to the dibaryon interpretation.