  We study the production of clusters and hypernuclei at midrapidity employing
the Parton-Hadron-Quantum-Molecular-Dynamics (PHQMD) approach, a microscopic
n-body transport model based on the QMD propagation of the baryonic degrees of
freedom with density dependent 2-body potential interactions. In PHQMD the
cluster formation occurs dynamically, caused by the interactions. The clusters
are recognized by the Minimum Spanning Tree (MST) algorithm. We present the
PHQMD results for cluster and hypernuclei formation in comparison with the
available experimental data at relativistic energies. PHQMD allows to study the
time evolution of formed clusters and the origin of their production, which
helps to understand how such weakly bound objects are formed and survive in the
rather dense and hot environment created in heavy-ion collisions. It offers
therefore an explanation of the 'ice in the fire' puzzle. To investigate
whether this explanation of the 'ice in the fire' puzzle applies only to the
MST results we study also the deuterons production by coalescence. We embed MST
and coalescence in the PHQMD and UrQMD transport approaches in order to obtain
model independent results. We find that both clustering procedures give very
similar results for the deuteron observables in the UrQMD as well as in the
PHQMD environment. This confirms that our solution for the 'ice in the fire'
puzzle is common to MST and coalescence and independent of the transport
approach.
