  We study how interacting localized degrees of freedom are affected by slow
thermal fluctuations that change the effective local disorder. We compute the
time-averaged (annealed) conductance in the insulating regime and find three
distinct insulating phases, separated by two sharp transitions. The first
occurs between the deep non-resonating insulator and a rarely-resonating
insulator (or intermittent metal). The average conductance is always dominated
by rare temporal fluctuations. However, in the intermittent metal, they are so
strong that the system becomes metallic for an exponentially small fraction of
the time. A second transition occurs within that phase. At stronger disorder,
there is a single optimal path providing the dominant contribution to the
conductance at all times, but closer to delocalization, a transition to a phase
with fluctuating paths occurs. This last phase displays the quantum analogon of
configurational chaos in glassy systems, in that thermal fluctuations induce
significant changes of the dominant decay channels. While in the insulator the
annealed conductance is strictly bigger than the conductance with typical,
frozen disorder, we show that the threshold to delocalization is insensitive to
whether or not thermal fluctuations are admitted. This rules out a potential
bistability, at fixed disorder, of a localized phase with suppressed internal
fluctuations and a delocalized, internally fluctuating phase.
