So whilst replacing old light switches with new ones (nothing fancy this time just replacing scruffy ones with white ones) 2 rooms in my house have 2 wires going in to one of the ports and 1 wire going into the other. One has 2 into common and 1 in to l1 and the other 2 in to l1 and 1 into common. I’m assuming one of the switches is wired incorrectly and am curious as to why they would be wired like this? Again an assumption is that this is to continue the circuit through the house but why do this at the switch and not in one of the junction boxes? Help appreciated!