High-gain parametric down-conversion (PDC) is inevitably accompanied by cascaded up-conversion (CUpC) of PDC radiation in a nonlinear crystal even if CUpC is nonphase matched. Here we study experimentally and theoretically the spectral properties of broadband phase-matched and nonphase-matched CUpC radiation in a beta barium borate (BBO) crystal. Our calculations of the normalized second-order correlation function predict the super-bunching of CUpC radiation.