[Inky]

Yes, you can see how it might make sense as a two-step mix-up. One writer has Superman lose his powers on a planet with a red sun because he isn't exposed to yellow light. Another writer vaguely remembers that plot and thinks it was because Superman loses his powers when he is exposed to red light, and so you end up with a lot of random vaguely-related things that contradict each other.

In a game, "only under a yellow sun" might be a limitation worth mentioning if it could be set off by the wide range of random vaguely-related things that Superman's apparently has been over the years!