"...a limitation on numerics." My understanding is that measuring quantities smaller than the Planck limits is problematic. (IIRC, the energy of a photon neede

"...a limitation on numerics." My understanding is that measuring quantities smaller than the Planck limits is problematic. (IIRC, the energy of a photon needed to make the measurement is large enough to create a black hole.) As a result, it's not just "numerics"; the theory may be symmetric, but the physical system cannot be observed to be.