My Permalink custom url is /%post_id%/%postname%/
and my website is in Persian language, for some posts the Permalink is change in URL from
but this doesn't happen for all post, for e.g following post works fine: ahangbaz.com/1106/%D9%82%DB%8C%D8%B5%D8%B1-%D8%A8%D8%B9%D8%AF-%DA%86%D9%86%D8%AF-%D8%B3%D8%A7%D9%84/
I checked in wp_posts table of wordpress and Post_name seems similar for both posts.
If I change the post_name to English it works fine but when post_name is in Persian,problem occures. web server is IIS 7.5 on windows 2008 R2.
I changed the thema and disabled all plugin, it still happens. I checked DB colation and its UTF8.
To reproduce the issue use the post_title = ابی - طپش - چشمه and post_name will be %d8%a7%d8%a8%db%8c-%d8%b7%d9%be%d8%b4-%da%86%d8%b4%d9%85%d9%87
The same problem happens with categories when the slug is in Persian ahangbaz.com/category/%d8%a7%d8%a8%db%8c doesn't work but when its in English or a number it works ahangbaz.com/category/22.