>
> is this a bug, or i am doing something wrong?
>

Probably neither.
Uuid is defined as char(16) character set octets. The results you get depend on your client application and whether it can format uuids the way you want it to.
If you use flamerobin, for example, you would get 32 characters, 16 bytes formatted as hex (although still not uuid format).

You can write your own UDF to represent uuid in a format that you need.

Sasha