Well, i could fix it removing the code: in plugins/system/sef/sef.php (line 51).

Hello, I have UTF-8 enabled and disable the automatic generation canonical link. When a link has a UTF-8 character link rel = "canonical" is automatically added to the link.

As I mentioned this problem happens only when the URL has an UTF-8 character.

I hope you can help me, unfortunately I think it's a bug.

I'm using the JoomSEF 4.3.0