  It is argued that the experimentally observed baryon stopping indicates a
non-monotonous behaviour as a function of the incident energy of colliding
nuclei. This can be quantified by a midrapidity reduced curvature of the
net-proton rapidity spectrum and reveals itself as a zigzag irregularity in the
excitation function of this curvature. The three-fluid dynamic calculations
with a hadronic equation of state (EoS) fail to reproduce this irregularity. At
the same time, the same calculations with an EoS involving a first-order phase
transition and a crossover one into the quark-gluon phase do reproduce this
zigzag behaviour, however only qualitatively.
