We present an internal outlook of the processes causing performance degradation in bipolar SiC devices. The dynamics and optical properties of structural instabilities in the active area of the operating PiN diodes have been investigated in situ by the technique of time-resolved optical emission microscopy. A spatial and spectral content of both electroluminescence (EL) and photoluminescence (PL) was analyzed to identify optical signatures of the growth and operation-induced structural defects. We demonstrate that by spectrally-selective imaging of integral luminescence the intrinsic stacking faults (SFs), partial dislocations (PDs) that bound these faults and also threading screw dislocations can be discretely visualized. The temperature and injection dependencies of recombination-enhanced motion of leading PDs have been quantified, providing an activation enthalpy for dislocation glide. Finally, we discuss specific sites on the partials where recombination enhancement of this motion may take place.