As in, the player you are facing has 900 Rift Rating, but they are level 50? Rift Rating isn't tied to your player level, so it's possible for this to happen, though I agree it's not ideal.
We do have discussed (no promises) some adjustments to matchmaking to help prevent matches from taking place if you and the opponent's collection are extremely far apart. We have some other things we may end up trying as well. We'll speak more on that in the future!
No, I mean that after usual win and loos swing then I finally close to new lifted limit of lowest rank (special thanks for that), I take series of much stronger opponents. It does not look like an accident, because it lasts about 5 times (±2, every time on less points