  Motivated by the recent low-threshold measurements of the solar 8B neutrino
spectrum performed by Borexino, Super-Kamiokande and the Sudbury Neutrino
Observatory -- all now monitoring the transition regime between low-energy
(vacuum-like) and high-energy (matter-dominated) flavor conversions -- we
consider the role of sub-dominant dynamical terms induced by new
flavor-changing interactions. We find that the presence of such perturbations
with strength ~ 0.1 G_F is now favored, offering a better description of the
anomalous behavior suggested by the new results, whose spectrum shows no sign
of the typical low-energy upturn predicted by the standard MSW mechanism. Our
findings, if interpreted in a 2-flavor scheme, provide a hint of such new
interactions at the ~ 2 sigma level, which is rather robust with respect to
3-flavor effects possibly induced by non-zero theta_13.
