Missing Menu Item id from wordpress menu

I have just noticed that my menu items id are not getting generated by wordpress.

I expect it to be something like this

<li id=’menu-item-2091′ class=’menu-item menu-item-209′>user_login; ?>’>Profile

but i get this without the menu item id.

<li class=’menu-item menu-item-209′>user_login; ?>’>Profile

This error is occurring in my main menu, but my top menu seems to generate the menu item id properly.

I have looked around the menus area and can’t find any clues why??