I just upgraded to 3.0.21 on Windows 7.
HTTP PATCH requests do not pass through, it seems.
I am doing local development, so unfortunately I don't have any live examples to give.
I'm not using any other proxies.
I'm running Chrome 26.0.1410.64 m.
From the source urlmatch.c, unknown_method(), it seems that PATCH is not yet supported.