On 2020-01-18 (build 525), selenium-daily-beta-MediaWiki (targeting https://en.wikipedia.beta.wmflabs.org) started failing with error message:
There seems to be a problem with your login session; this action has been canceled as a precaution against session hijacking. Please resubmit the form.
On 2020-01-20 (build 199), selenium-daily-betacommons-MediaWiki (targeting https://commons.wikimedia.beta.wmflabs.org) started failing too.
@Cparle and I have tried to log in to https://en.wikipedia.beta.wmflabs.org manually several times, and it works sometimes, sometimes we get the above error message.