Canonical is wrong, menu item is not used first

[Kuubs]

I have a weird bug. When I set a menu item for a specific product, but also have a category menu link, it will not use the menu item with the product directly as canoncial url, but it will use the category menu link.

root.com/product1

but it uses this one:

root.com/category1/product1

While i have a menu product link. It should always have this direct menu product link as main product link...  Any idea how to fix this?