In this work, the first evidence of the recombination-induced formation of hydrogen complexes with Si vacancies (V-Si-H) in 4H and 6H-SiC epilayers is obtained. It is established that the availability of hydrogen that is not tied up with stable complexes following plasma hydrogenation leads to the additional formation of the V-Si-H centers under optical excitation at low-temperatures. This process may be observed as an increase of the V-Si-H PL in certain types of hydrogenated samples. The PL transient is found to be a superposition of two effects: (1) the growth due to the recombination-induced formation of the corresponding defect centers; and (2) the quenching due to the transition of the V-Si-H centers to their metastable state.