Analysis and test of the central-blue-spot infall hallmark (Corrigendum) R. Estalella, G. Anglada, A. K. Díaz-Rodríguez and J. M. Mayen-Gijon A&A, 647 (2021) C2 Published online: 09 March 2021 DOI: 10.1051/0004-6361/201834998e