  In this work we identify and investigate a novel bifurcation in conserved
systems. This secondary bifurcation stops active phase separation in its
nonlinear regime. It is then either replaced by an extended, system-filling,
spatially periodic pattern or, in a complementary parameter region, by a novel
hybrid state with spatially alternating homogeneous and periodic states. The
transition from phase separation to extended spatially periodic patterns is
hysteretic. We show that the resulting patterns are multistable, as they show
stability beyond the bifurcation for different wavenumbers belonging to a
wavenumber band. The transition from active phase separation to the hybrid
states is continuous. Both transition scenarios are systems-spanning phenomena
in particle conserving systems. They are predicted with a generic dissipative
model introduced in this work. Candidates for specific systems, in which these
generic secondary transitions are likely to occur, are, for example,
generalized models for motility-induced phase separation in active Brownian
particles, models for cell division or chemotactic systems with conserved
particle dynamics.
