We have seen that players are sometimes losing significant amounts of MMR after a match has ended, with no indication that it was a roll back from a cheater being banned.

Our team is currently investigating. As a precaution, we have deactivated the MMR Roll Back feature while we determine the root cause. For those of you curious about the intended functionality of the MMR Roll Back feature, you can learn more here.

We will update you further when we have more information.

UPDATE 1

We have found that the pop up to notify players their MMR is being rolled back is not triggering, and thus not being displayed when a roll back has occurred.

Additionally, matches that needed to be rolled back were not flagged as "complete" once the MMR was removed from players in that match. This lead to roll backs occurring multiple times for the same match, creating larger than intended losses.

UPDATE 2

We have confirmed that we have a record of all MMR lost due to this issue, and will be able to ...

dazzathomas

Will those affected have their MMR returned to the previous amount upon further investigation?

Nice to see the acknowledgement so quick, given that it's the weekend!

Our focus right now is determining the issue. Once that is fixed we will begin discussions for next steps regarding impacted players.

FaZzyTheGod

Have you guys also looked into people getting matched with players from different regions on PC? I’ve been ranked with Brazilian players and server is EUS and it is really frustrating to have 100+ ping.

Yes. We are rolling out a fix for that early this coming week.

SolidSneakNinja

Is it PC only or is console affected? I'm on PS4 as well.

As far as we have seen it is PC only.

T0rdenguden

Played vs a cheater, lost the match the cheater gets banned i still haven't received my Lost MMR, is MMR rollback even working as intended ?

this happened 2 days ago

It is not an instant refund. Regardless, it is not working as intended given the current issue at hand, but we don't know to what extent.

phellipecascardo

PS4 also is crossing servers and we cant change like PC does. I’m from Brazil and been playing at EUS with +100 ping ☹️

Yes, we know.

Youremomsyouredad

I bet there was A LOT of messages waiting for you today.

More than 3.

BoycottLeafy

Im a console player, just wondering what MMR means?

Matchmaking rating. It's how we identify skill levels for matchmaking and ranks.

dryyour3yes

Hey are you the Epi taht was in Dota Esports a few years back?

Nope

shingofan

Sounds like a stray typo got into the filter

Precisely!

JazzShadow2

Bit sorry to beat a dead horse but, any progess on the game freezing, mostly on dual core cpus?

Does your dual core CPU have hyperthreading enabled?

JazzShadow2

No, it doesn't support hyper-threading.

We do not support 2 cores with hyperthreading disabled. Rainbow Six Siege needs at least 4 cores/threads to run reliably.

We are updating the FAQ on the customer support page to be more clear.

SpawnPeekDaily

Damn too bad I’m perma banned from typing the letter v

That isn't a thing. The filter has nothing to do with bans.