Nostalgic flashback to Premier Manager games, where players stats decreased as they aged. When they went /below 0/ they flipped around to 127. So a good strategy was to scout out really bad players from lower leagues about to hit age 30+. And offer them very long contracts to prevent them retiring .. and give time for most of their stats to flip around, turning them into superstars.
The bug never existed at all in Civ 1. It was an urban legend all along. Similar behavior was intentional in Civ 5 as a joke, which convinced everyone that it really did happen in Civ 1 when it never did.
