Hi,
The confusion of Itemid must have caused that. It is a joomla thing.
If you have a organized Menu Manager, this confusion won't happen again. It is always good to keep the menu manager well-organized. Create a menu item for pages you use in the website, and if you are linking sub-pages with manual URL, then make sure to include the itemid at the end. There should be no link in your website (internally) without an itemID at the URL, because if the itemid is blank, joomla will use the previous page's itemid automatically, which will break the breadcrumbs.
Case solved. Topic is closed.
Regards,
Support