Had no idea this was a bug, though it has little effect for three reasons.
1. It'd be hard as heck to increase the population further because of how much Food you'll need to cultivate.
2. That's nearly the population of America in 1996-2001 when Civ2 was at its apex of glory. Only two IRL nations (India and China) have more people. In other words, it'd be difficult for even a prodigy player (which I'm not) to build a better civilization.
3. That far down the line, Future Techs are the only other realistic way to get a higher score (not sure if they have a "loop break" bug though it's possible given how dated the game's engine is compared to even Vanilla Civ3's).
TL, DR - definitely a bug, but it's so minor as for average and novice players to barely (if ever) notice.