You mean similar to this?
	
	
	
		Code:
	
	
		https://xenforo.com/community/threads/how-to-customize-the-post-link.209733/post-1595944
	 
 This adds the specific post number to the title also.  Expected behavior as that's how XF tracks the posts.
If you are referring to the escape characters in your example... the 
Romanize Titles in URL is supposed to take care of that from what I understand.
But some characters reflect as you demonstrated, ergo the 
when possible in the comment of that function. And generally it's been Vietnamese or a similar Asian language every time I've seen it.[/code]