I am getting a failed schema validation error while trying to upload a 100+ MiB WebM file to Commons using the UploadWizard.
The error message is: "Validation error against schema UploadWizardFlowEvent: Unrecognized property: quantity".
This happens with chunked uploads enabled (since it's a file bigger than 100 MiB), both with and without the HHVM beta feature.
I am using Iceweasel 31.2.0 on Debian Wheezy, but the same thing happened when I tried using the newest stable version of Google Chrome before (38.0.2125.104-1) and encountered the same issue.
I have successfully managed to upload multiple 100+ WebM videos before, most recently at the end of September.