Hi everyone. Sorry for the quiet on this one. We made a change to part of our widget code a number of weeks ago and hoped it would resolve the issue, as we’ve never been able to reproduce it in isolation. Along with Frank and Christian above we had another report today so we’re looking again. I’m going to push out a patch shortly that should prevent it from happening.
We’ve narrowed the cause of the error to only occurring in Firefox, with some undetermined extension installed. We cannot reproduce the error with raw, extensionless versions of Firefox installed, which we think explains why there aren’t an overwhelming quantity of reports. On the other hand, there are enough reports that whatever extension is malfunctioning must have a reasonable install-base. I suspect it’s a pre-caching, or speed optimisation extension, because what’s happening is that it’s misidentifying your page’s (encoded) URL inside of another URL parameter inside of the widget, and proceeding to to access it, with the remainder of the query string appended.
I worked my way through some of the more popular Firefox extensions matching this description this evening, but none enabled me to reproduce the error. We’ll put in a work-around regardless as best we can, but if anyone happens to have some insight into Firefox add-ins that might be a culprit, we’d love to test it more thoroughly.
Thanks everyone for your patience, and apologies for the delay.