  Parity-time (PT) symmetric systems have two distinguished phases, e.g., one
with real energy eigenvalues and the other with complex conjugate eigenvalues.
To enter one phase from the other, it is believed that the system must pass
through an exceptional point, which is a non-Hermitian degenerate point with
coalesced eigenvalues and eigenvectors. In this letter we reveal an anomalous
PT transition that takes place away from an exceptional point in a nonlinear
system: as the nonlinearity increases, the original linear system evolves along
two distinct PT-symmetric trajectories, each of which can have an exceptional
point. However, the two trajectories collide and vanish away from these
exceptional points, after which the system is left with a PT-broken phase. We
first illustrate this phenomenon using a coupled mode theory and then exemplify
it using paraxial wave propagation in a transverse periodic potential.
