  Three galaxy clusters selected from the XXL X-ray survey at high redshift and
low mass ($z\sim1$ and $M_{500} \sim 1-2 \times 10^{14}$ M$_{\odot}$) were
observed with NIKA2 to image their Sunyaev-Zel'dovich effect (SZ) signal. They
all present an SZ morphology, together with the comparison with X-ray and
optical data, that indicates dynamical activity related to merging events.
Despite their disturbed intracluster medium, their high redshifts, and their
low masses, the three clusters follow remarkably well the pressure profile and
the SZ flux-mass relation expected from standard evolution. This suggests that
the physics that drives cluster formation is already in place at $z \sim 1$
down to $M_{500} \sim 10^{14}$ M$_{\odot}$.
