Well, oil filter should be changed everytime you change your oil. Unless you have an extended guard like me and it's good for 12000 km. Otherwise oil filter is changed during an oil change.
It could be that who ever changed the oil did not tighten the oil filter tight enough, but that's just my guess. You have to find the source of the leak.
It could be that who ever changed the oil did not tighten the oil filter tight enough, but that's just my guess. You have to find the source of the leak.