I didn't notice her accent was particularly bad. I've certainly heard worse coming from much more experienced and higher paid actors, so I think we can let her off. If anything I thought it had a slight Canadian twinge, but that's not surprising.
I really must watch the webisodes for this as I downloaded them a while ago but only watched the first five or ten minutes.
Oh and as for people loosing their accent away from home, I can certainly attest to that. In school I had a tech teacher who had a right middle class accent. Wasn't until my last year that we found out she was originally from Nevada.