I've noticed a small issue with my email client for quite some time now where composing a new email will have several blank lines by default.
It's not too much of an issue to simply delete them but hey, maybe no one had pointed this out before! So I filed a bug report only to get this response... basically it's not a bug, its a feature!
My point is that someone made the decision for it to do that and that the software works just fine as is. It's not a bug, it's just a weird quirk. The fact that they made the enhancement you requested doesn't make the old behavior buggy. Your post title said "it's not a bug, it's a feature!", but the behavior you reported is not accurately classified as a bug.