  We study stability conditions of the full Hamiltonian constraint equation
describing the quantum dynamics of the diagonal Bianchi I model in the context
of LQC. Our analysis has shown robust evidence of an instability in the
explicit implementation of the difference equation, implying important
consequences for the correspondence between the full LQG theory and LQC. As a
result, one may question the choice of the quantisation approach, the model of
lattice refinement, and/or the role of the ambiguity parameters; all these
should in principle be dictated by the full LQG theory.
