An update has been released for Portal 2.

• Fixed issue with recent workshop maps that prevented voting on them or advancing past them in the quick queue.
• Fixed workshop map thumbnails not loading in the community map voting dialog.
• Removed workshop map download limits for subscribed maps introduced in the last update, and increased the limit for the history queue to 500 by default. The history queue size is also now a convar, cm_max_history_chambers, so it can be increased if desired.