  We consider a two-component regular cosmology bouncing from contraction to
expansion, where, in order to include both scalar fields and perfect fluids as
particular cases, the dominant component is allowed to have an intrinsic
isocurvature mode. We show that the spectrum of the growing mode of the Bardeen
potential in the pre-bounce is never transferred to the dominant mode of the
post-bounce. The latter acquires at most a dominant isocurvature component,
depending on the relative properties of the two fluids. Our results imply that
several claims in the literature need substantial revision.
