A modified version of loop quantum cosmology model, the so-called mLQC-I, motivated by Thiemann’s regularization of the Hamiltonian constraint, leads to the resolution of the big bang singularity and a bounce in the isotropic setting, where either the pre- or postbounce epoch is necessarily characterized by an emergent Planckian de Sitter phase. In this work we explore the Planckian physics of this mLQC-I prescription for the Bianchi-I spacetimes. We show that, as in the isotropic model, there exists an emergent de Sitter phase which naturally dampens anisotropic shear and removes cosmic hair. However, this isotropization comes at a steep price: although a macroscopic postbounce regime is achieved, the universe does not become classical. As is well known from the Kasner solution, the classical evolution of a contracting Bianchi-I universe toward the singularity can in general be either point- or cigarlike. However, cigarlike evolution is prevalent unless the matter content dominates over the anisotropic shear. For a class of physically admissible initial conditions corresponding to cigarlike evolution, we further demonstrate that this isotropization mechanism is nongeneric. These results clarify and reinterpret recent claims by Gan et al. [Phys. Rev. Lett. 136, 251501 (2026)] that, in anisotropic mLQC-I, quantum gravity effects generically damp anisotropic shear in a manner independent of initial conditions and matter content, and that this damping arises from a novel quantum gravity effect. Our work explains the origin of this mechanism and its limitations in the mLQC-I model.

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• Loop quantum gravity
• Quantum cosmology