This is an effect found in a process A + BC when the attacking species A is heavy. Because A is heavy the A–B distance continues to decrease while the repulsive energy of B–C is being released.
Source:
PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 174 (https://doi.org/10.1351/pac199668010149)