I ran a PCR for seaweed samples using cox2-3 spacer Cox2 forward and cox3-Reverse, I got a PCR product around 360 bp (with sample 1,37) with both annealing temperatures 48 and 50 ͦC as it is shown in the gel image attached. However, I got two PCR products with sample 36 (one around 600 bp, the other around 360 bp), How this can happen and what it means?

Note: + means positive control, - means negative control, E means empty (no sample is loaded), L (100 bp DNA ladder)