  In light of the tension between cosmological parameters from Planck cosmic
microwave background and galaxy clusters, we revised the Planck analysis of the
$Y_{SZ}$-mass calibration to allow evolution to be determined by the data
instead of being imposed as an external constraint. Our analysis uses the very
same data and Malmquist bias corrections as used by the Planck team in order to
emphasize that differences in the results come from differences in the
assumptions. The evolution derived from 71 calibrating clusters, with
$0.05<z<0.45$, is proportional to $E^{2.5\pm0.4}(z)$, so inconsistent with the
self-similar evolution ($E^{2/3}$) assumed by previous analyses. When allowing
for evolution, the slope of $Y_{SZ}$-mass relation turns out to be
$1.51\pm0.07$, which is shallower by $4.8\sigma$ than the value derived when
assuming self-similar evolution, introducing a mass-dependent bias. The
non-self-similar evolution of $Y_{SZ}$ has to be accounted for in analyses
aimed to establish the biases of Planck masses.
