yeah that's kinda weird, if you meant quality(picture)-wise, my episode 7 looked exactly the same quality as any other of the episodes, maybe you dl'd a re-encoded version? otherwise, if that's not the case, you should crc it or something cause there shouldn't be much of a difference between that episode and any of the others.. although I just checked, I only have 7,8,9 on my comp still, but apparently I'm using divx low-motion codec for that ep, yet 8 and 9 both use xvid, but that makes sense since those two eps are recently released.
good luck!