Why are the white stones in the bottom left of this game counted as points for black?
It is possible depending on previous turns that some variants of the Superko rule would allow black to win that fight. For example, if black played A3, white might not be allowed to capture at A5 if that position had already appeared earlier in your game. However, even if that rule is in effect and relevant, I doubt it would be incorporated into the scoring system, so my guess is this is just a bug in the digital adaptation.
EDIT: PJTraill comments that we can see from your picture that H8 was the most recent move; since that space was empty before and is now filled forever, no earlier positions should be relevant for Superko. Thus there is no way to break that seki.