It happened to me 3 times now and the most recent one was just about a month ago, I think I was just in the 60k-ish rank with 2.2kpp when suddenly I noticed something odd in my
gameplay. Then, after a while of practicing since I'm just getting used to my new playstyle, I managed to fc maps beyond 4.7* (which was my highest fc so far that time) and eventually, I started passing 5* and even fc'ing some of them. Went from 60k to 40k in about a month.
Still surprised tho that all my top plays (except one) are submitted within a span of 2 months xDMy opinion on this is maybe players overcome certain "walls" in their improvement and when they finally get over it, they just easily charge through the rankings till they come across another wall in their gameplay.