join a ranked server at rank 630
beat a player at rank 500
no change between his or my rank
win a game against an unranked player
he gets my 630 rank and i go to rank 632
play against rank 500 and win
i stay at 632 and he goes to 634

Theres nothing bad at this. As u can see, You have pretty bad elo. With bad elo your rank will not get better. Ranks has allways worked with elo. Get better elo = Better rank. Thats simple. Whats the problem here?

If your elo (the number in brackets after the rank) is higher than the person you're fighting, and he has a better rank, winning against him will probably give you his rank, or at least you'll go up alot more. And losing against him will only make your rank go down a bit, and his rank will go up just a little bit.

Often ranks dont update with Elo immediately, because of reasons , wait 2 hours or so