I dunno. That B does look suspicious now that I see it. Still, you said it was moving. You've only got a few days to go so I would for sure leave it in there. I've had worse questionable ones I left in there with question marks on them and in one of my last hatches a question-marked egg...
To me it looks like air cells on both of them but the one on the right is a little bit larger. Since they are both the same age egg in the same incubator, they should be very close to the same. It still could be okay and sometimes they're sleeping or tired when we candle them. Since it's...