Happened today on Linux Ubuntu 12.10 (x86) with Nightly fr : http://mozmill-ci.blargon7.com/#/functional/report/5aa1ca5e7015e3740d269dc9476ad448
Are you able to reproduce this failure?
I tried to reproduce it locally today and wasn't able. This has only happened once in the last 2 months (up to 01.06.2013) and it might be due to a problem with AMO rather than with our tests.
Happened again on Mac 10.7.5 (x86_64 with Aurora de, I couldn't reproduce it locally http://mozmill-daily.blargon7.com/#/functional/report/fb97b6210ae70da1b9ace67445c045fe
We haven't seen this since 11.09.2013 and I cannot reproduce it. I think it's safe to close as WFM, please reopen if it happens again.