Proving a certificate of graduation is no guarantee of common sense
It can be tricky to figure out what causes bad behaviour in a dog, but it's amazing how quickly some experts can sort it out - the team on BBC's Dog Borstal http://www.bbc.co.uk/bbcthree/programmes/dog_borstal/ and Cesar Milan http://dogpsychologycenter.com/dogwhisperer/ being two great examples.
She is not bad, just stubborn, and she thinks she knows better than all of us LOL She will do it when SHE wants to do it, not when you tell her she should. It's not a lack of common sense as much as an air of superiority. A common beagle trait, but we love her nonetheless. Sadly, she is on her last legs, poor girl.