  Factorized spectral surface scenario has been considered as one of solutions
to the dimension-4 proton decay problem in supersymmetric compactifications of
F-theory. It has been formulated in language of gauge theory on 7+1 dimensions,
but the gauge theories descriptions can capture physics of geometry of F-theory
compactification only approximately at best. Given the severe constraint on the
renormalizable couplings that lead to proton decay, it is worth studying
without an approximation whether or not the proton decay operators are removed
completely in this scenario. We clarify how the behavior of spectral surface
and discriminant locus are related, study monodromy of 2-cycles in a
Calabi--Yau 4-fold geometry, and find that the proton decay operators are
likely to be generated in a simple factorization limit of the spectral surface.
A list of loopholes in this study, and hence a list of chances to save the
factorized spectral surface scenario, is also presented.
