I have sort of a similiar problem myself.
My bike is an '01 with original battery in it.
When i'm riding, it's fine. But what i experienced was, when i got caught in a traffic jam, more than once recently i stopped to get a pack of smokes at the convient store and when i came out to start my bike, it was dead.
I bump started it, then rode the rest of the way to work via back roads. When i got to work i shut the bike off, got undressed then i wanted to see if the bike would start, it did. So at the end of my work day i went to go home and the bike started no problem. it happened after that also in the same situation. I think the battery is on it's last leg personally.
Am i right????