  The recent measurement of helium-4 from the near-infrared spectroscopy of
extremely metal-poor galaxies (EMPGs) by the Subaru Survey may point to a new
puzzle in the Early Universe. We exploit this new helium measurement together
with the percent-level determination of primordial deuterium, to assess
indications for a non-vanishing lepton asymmetry during the Big Bang
Nucleosynthesis (BBN) era, paying particular attention to the role of
uncertainties in the nuclear reaction network. A cutting-edge Bayesian analysis
focused on the role of the newly measured EMPGs, jointly with information from
the Cosmic Microwave Background, suggests the existence of a nonzero lepton
asymmetry at around the $2 \sigma$ level, providing a hint for cosmology beyond
$\Lambda$CDM. We discuss conditions for a large total lepton asymmetry to be
consistently realized in the Early Universe.
