Permalink problem portfolio related

Hello I have a problem with the permalinks.

When I enable it as for example: “/%year%/%monthnum%/%day%/%postname%/” webiste pages doesn’t work anymore returning a 404 not found.

Investigating it I found that it tries to find the pages with a wrong wp_query.
This is the query array it uses when I click a page (not a portfolio item):

[query] => Array
        (
            [page] => 
            [name] => contacts
            [post_type] => portfolio
            [portfolio] => contacts
            [debug-this] => wp_query
        )

while instead it should use this one:

[query] => Array
        (
            [page] => contacts
            [name] => contacts
            [post_type] => page
            [portfolio] => 
            [debug-this] => wp_query
        )

Have some idea why?