Yeah, I agree with others that based on what I and others have seen, it seems it did immediately count win streaks prior to the changes, but it does also seem like it only looks at the last 30 days or so.
This is still an absurd system though since yes, you just shouldn't play players you have multiple wins against in a 30 day period but
1) you can't pick your opponents in arena
2) other games player pools are not large enough to allow this
3) If you use the service a lot, it's easier to be hit by this, however you can easily be playing enough variety of opponents there's no reasonable claim you're power leveling off any individual
4) Really problematically, this punishes higher player count games much more since it counts beating opponents as win streaking, even if you're not actually winning
Also, ever since this change they've also (Presumably accidentally) introduced the old issue of when someone quits a multiplayer game, if you're a highly ranked player, you can lose elo. Losing elo when someone else quits is absurd, and it has been corrected in the past, but now it happens again. If I wind up in an arena Agricola game against some more mid range players, and one of them quits, I'll lose elo at the moment. How this issue continues to crop up and reoccur and not be fixed is stunning.
I can't understand how the BGA admins have read this thread and not made changes for a month now. I can't understand how an issue like losing elo due to a quitter in multiplayer games crops up again--this was fixed in the past, then cropped up when they introduced elo and then fixed, and now they've made another elo change and it comes up again. How does this get past your testing anymore? It's a known issue from the past, you've been told you had to correct it and did, and then somehow it's not on a test case list when you make a change???
You have tons of users frustrated about power leveling and you're creating absurd incentives for your players to avoid playing each other, and yet you don't fix it?
I and many others love this site and what it offers, but gosh the management frustrates me sometimes.