Upgrading to the last version yesterday I get an error viewing a page that contains a link field.
The error says: "warning: "preg_match() expects parameter 2 to be string, array given in /xxx/xxx/includes/bootstrap.inc on line 777".
This behaviour didn't happen before.
I have a custom content type with a field of type 'Link'. When I set the display of that field to 'URL, as plain text' or to 'hidden', the error disappears.
But once I change the display to 'Title, as link' or 'URL, as link' or ... the error shows up.
The URL itself is nothing special: http://www.example.com/node/69.