Then i would say you should keep a very close eye on your hairline, an unever CAN be genetic , it can also be a sign of male pattern baldness, my recession started on the left side, my left side is still higher than my right, fortunately i started finasteride so hopefully it can keep my right side at a Norwood 1.5 and stop any loss on my left side.
As a general rule , male pattern baldness is rarely symetrical , so if one side has receeded more than the other, if you do have male pattern baldness then the other side will catch up eventually and the process will continue.