Erratum to: The two-loop energy–momentum tensor within the gradient-flow formalism Robert V. Harlander, Yannick Kluth and Fabian Lange Eur. Phys. J. C, 79 10 (2019) 858 Published online: 18 October 2019 DOI: 10.1140/epjc/s10052-019-7327-x