I have noticed that myself
I hunt in West TN and Oct 20-27 is normally about the start of the rut. Well I hunted all of bow season and never saw a scrape, rub, or buck running a doe. When I returned home to hunt for our first rifle season, I still had no sign to hunt. However, on the last few days I noticed that several ruts appeared on the edges of the field, rubs were on the cedar and pine trees that border my two largest fields, and I heard a buck running a doe and grunting. I am returning home the 20-27 to finish up rifle season and am hoping the deer will be in middle, to late rut.
I think most of the late rut was a result of the drought that occured in the south. There was and still is little vegetation and I know in my area a very very very small acorn crop. So the deer had little nutrients this year, along with a very harsh heat conditions, and not to mention the EHD problem occuring in many southern states because of the harsh conditions.