So first off this message is expected and is normally there on all Cls passed through CQ. What's not expected is that this message is not hidden behind "show generated messages". 

Meaning, either new bug in Rietveld + recent Rietveld deployment, then this should be on all CLs, which I don't yet observe, weird. Or maybe something weird in CQ.

I've checked Rietveld appengine version: the current one is serving since June 6. So, I think this must be a bug in CQ.

Hm, but most recent CL on chromium doesn't have this problem:  https://codereview.chromium.org/2061663002

I'm not sure if it's on every CL, but it's definitely on a lot of CLs, scrolling here through to 9 June. https://groups.google.com/a/chromium.org/forum/#!searchin/chromium-reviews/%22CQ$20bit$20was$20unchecked%22%7Csort:date

Does whether it's a generated message determine whether mail is sent?

my https://codereview.chromium.org/2069603002/ from just now definitely sent me an extra email due to "cq bit unchecked" when it landed

Re-assigning to Sergiy who is THE real hero this week.

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/infra/infra_internal.git/+/8b91dc28f36475647ecd1637422b762b062052f6

commit 8b91dc28f36475647ecd1637422b762b062052f6
Author: Sergiy Byelozyorov <sergiyb@google.com>
Date: Tue Jun 14 21:35:25 2016

Fix: https://chromereviews.googleplex.com/452677013/

I got this on https://codereview.chromium.org/2065373002/ today too. Is the fix supposed to be live already?

It wasn't fixed then. Thanks for heads up!

Looking at this now.

So, as usual with parallel synchronization, the fix wasn't quite sufficient. A clean separation of concerns between thread is needed.

Crap, still happening: https://codereview.chromium.org/2130713002/

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/infra/infra_internal.git/+/8bafd9c11fc311b1a84d3b3fd8c970c590154980

commit 8bafd9c11fc311b1a84d3b3fd8c970c590154980
Author: tandrii <tandrii@google.com>
Date: Wed Jul 20 19:36:06 2016

And I think I've finally resolved it with CL above. Since it was deployed ~48 mins ago, I don't see a single such message in CQ logs, but I immediately see 8 in an hour before that.

Metrics don't have a single such message ever since I've committed this. FIXED!!!

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/infra/infra_internal.git/+/7ec635b91c86c3ca92be41a1e68cdf45bb45b389

commit 7ec635b91c86c3ca92be41a1e68cdf45bb45b389
Author: tandrii <tandrii@google.com>
Date: Thu Jul 21 14:04:39 2016

Thanks Andrii!