Probably related: last week if you looked at ladder it said there are ~3500 players (which means active players). If I look now the ladder is ~2000 players. As rank progression is determined by "when will you get to X % of ladder" a changing number of active players will directly affect your progression. (funny fact: you might rank up if you bring enough players that play constantly).
Not sure how is this related to server reset, it can also be that we are one month away from Christmas vacation (so anybody that played during vacation became inactive.
Edit: side effect of less active players: jump in the ladder. Last week I was ~90 now I am ~70.
