  Superconducting granular aluminum is attracting increasing interest due to
its high kinetic inductance and low dissipation, favoring its use in kinetic
inductance particle detectors, superconducting resonators or quantum bits. We
perform switching current measurements on DC-SQUIDs, obtained by introducing
two identical geometric constrictions in granular aluminum rings of various
normal-state resistivities in the range from $\rho_\mathrm{n} =
250\,\mu\Omega\mathrm{cm}$ to $5550\,\mu\Omega\mathrm{cm}$. The relative high
kinetic inductance of the SQUID loop, in the range of tens of nH, leads to a
suppression of the modulation in the measured switching current versus magnetic
flux, accompanied by a distortion towards a triangular shape. We observe a
change in the temperature dependence of the switching current histograms with
increasing normal-state film resistivity. This behavior suggests the onset of a
diffusive motion of the superconducting phase across the constrictions in the
two-dimensional washboard potential of the SQUIDs, which could be caused by a
change of the local electromagnetic environment of films with increasing
normal-state resistivities.
