Period exactly 2 days late for the past 4 months

My period has always been on the dot. Not late or early and never missed. But the past few (like 3 or 4) months it seems like it has been exactly 2 days late. I'll record it as being late on my chart and it'll bump my period 2 days away and then it shows up that day. Anyone else have this? Just wondering what it could be from. There is no spotting from the day it should have originally arrived to the 2 days away when it actually arrives either. No cramps either.