Recently I've been assigned a bug to fix, which from my point of view, was actually a change request. After some investigation it turned out that this bug was caused by a defect in business requirements, but it was still considered as a bug.
I often see change requests being pushed forward masqueraded as bugs. I am just trying to figure out if there are any differences.
A "bug in requirements" means there was something wrong with how the functionality was originally designed.
A "change request" means that everything was defined correct, but the customer wants a piece of functionality changed/added.