  We study the geometrical instability arising in multi-field models of
inflation with negatively-curved field space. We analyse how the homogeneous
background evolves in presence of geometrical destabilisation, and show that,
in simple models, a kinematical backreaction effect takes place that shuts off
the instability. We also follow the evolution of the unstable scalar
fluctuations. We show that they assist the kinematical backreaction while
remaining in the perturbative regime. We conclude that, in the simplest models
of geometrical destabilisation, inflation does not end prematurely, but rather
proceeds along a modified, sidetracked, field-space trajectory.
