Last modified: 2012-10-09 18:36:21 UTC
Tracked down to I3e8227ddb87fd9441071ca935439fc6467751dab. Strange 404 errors are happening to URIs that look like they're comma-separated mashed together.
Fix in I32a79af637acb782e07bbae413b0f007350096c3. No released notes as it was a recent regression.