If a TAG permalink have chinese (Japanese) characters, the permalink of the TAG is like this:"/tag/%E4%B8%80%E6%A0%B7/"
In fact, the "%E4%B8%80%E6%A0%B7" is chinese (Japanese) characters. BUT, when a browser or a search engine spider visit or crawl the tag page /tag/%E4%B8%80%E6%A0%B7/, the wordpress3.0 will auto redirect "/tag/%E4%B8%80%E6%A0%B7/" to "/tag/%e4%b8%80%e6%a0%b7/".（lowercase）
Then the problerm comes, a lot of Chinese and Japanses user report that when upgrade to WordPress 3.0 the Google spider can NOT crawl there TAG page smoothly, the spider do not accept the 301, you can check the crawl errors and server log to see how the WordPress give a 301 when hit the TAG url and how Google report errors.
The WordPress2.71 or 2.92 user does not have this problem. But WordPress3.0 user will see a lot of redirect error in Google webmaster tool.
#14201says it is "The taxonomy redirect logic was added after 2.9 was released. Just nobody had tested with non-ASCII base. " but the patch in #14201 does not work. I am really anxious because there are 1k+ redirect errors in my Google webmaster tools. But it seem that this bug is not attract wordpress team members' attentions, they are just not the non-ASCII language user, so no one test the logic in non-ASCII base no one test the patch in non-ASCII base.
I want a reply or something say that "oh yes, we are working on it but we are so busy to test its compatibility in other languages even if the wordpress users are come from all over the world!!!"