  The standard treatment of quantum corrections to semiclassical electronic
conduction assumes that charge carriers propagate many wavelengths between
scattering events, and succeeds in explaining multiple phenomena (weak
localization magnetoresistance (WLMR), universal conductance fluctuations,
Aharonov-Bohm oscillations) observed in polycrystalline metals and doped
semiconductors in various dimensionalities. We report apparent WLMR and
conductance fluctuations in H$_{x}$VO$_{2}$, a poor metal (in violation of the
Mott-Ioffe-Regel limit) stabilized by the suppression of the VO$_{2}$
metal-insulator transition through atomic hydrogen doping. Epitaxial thin
films, single-crystal nanobeams, and nanosheets show similar phenomenology,
though the details of the apparent WLMR seem to depend on the combined effects
of the strain environment and presumed doping level. Self-consistent
quantitative analysis of the WLMR is challenging given this and the high
resistivity of the material, since the quantitative expressions for WLMR are
derived assuming good metallicity. These observations raise the issue of how to
assess and analyze mesoscopic quantum effects in poor metals.
