Mine used to have a similar issue with the home button, but I ignored it, and it seems to have gone away. I doubt you have a bad button.
I thought briefly of exchanging mine but decided against it because in doing so, I'd increase the chance of actually getting a bad unit (as opposed to a normal one with the usual occasional glitches that cause doubt). I figured that if it didn't go away, I'd be covered by the warranty. Glad I went that route!