@SteveF, I am a grower, which means that when I am flaccid I have some loose skin. I was about a CI-2.5 on the Coverage Index, but my skin was very tight when erect. Fortunately, I had a medium cut that left my skin somewhat loose when flaccid.

Between my first and second month I noticed that my skin started bunching up next to my corona. As I kept tugging, more and more skin bunched up. I also had spontaneous roll over during this time. This only occurred when my flaccid penis was shorter than normal, such as immediately after working out and when sitting down. And, it only occurred for a few seconds at a time. I also started retaining fulltime after about two months, so my foreskin was always forced over my glans.

The time to first rollover depends on how tight you were cut and if you are a grower versus a shower.  The Real Coverage Index is good for gauging restoration progress. If you were tightly cut, it will take longer than if you were cut loosely.