Two different and novel in-grown triangular stacking faults have been observed and characterized in 4H-SiC epitaxial layers grown on 4o off-cut substrates. The faults were formed at the beginning of the growth and extended continuously in size during the growth. Their structural and optical properties were however different as seen from both synchrotron white beam topography and low temperature photoluminescence. The luminescence spectra were similar but appeared in different energy regions 2.85 – 2.95 eV and 2.48 – 2.64 eV, respectively. BPDs present in the epilayer are found to be transformed into SFs under laser excitation during high resolution optically detected lifetime mapping. The faults are found to expand from the epilayer surface towards the epi-substrate interface. The optical spectrum from this fault is identical to the emission from the single layered Shockley stacking faults with excitonic bandgap of 3.034 eV previously only observed and formed in the bipolar diodes during forward voltage operation.