Maybe it was this ticket in September? https://phabricator.wikimedia.org/T146686 I’ll try to get a full stack trace later today when I have access to the wiki again. DanB From: Wikitech-l [mailto:wikitech-l-bounces@lists.wikimedia.org] On Behalf Of Alex Monk Sent: Monday, December 19, 2016 9:38 AM To: Wikimedia developers <wikitech-l(a)lists.wikimedia.org> Subject: Re: [Wikitech-l] VisualEditor in 1.28 - fails after upgrade from 1.27 I feel like that sessions error was something we fixed months ago but can't find details right now. Certainly not the first time I've seen it...