When entering a bug in a product that has more than 200 components, the description is retrieved via AJAX. We made a change to Component.get to non longer accept names that aren't in an array. As a result of this, the enter bug page does not function as expected for some core products.
Backported to 4.4-2 and 4.2-8 since bug 878013 was also backported.
This change is now live. -- simon