[salty] I'm not actually familiar with its usage in Steven Universe fandom, but based on how I've seen it used in fandoms since then, I'm willing to believe they may well have given it its "modern" meaning—in which people seem to use it to mean essentially just "this reminds me of something" rather than saying anything about what the creator intentionally put in. (No, nothing can be your-fave-pairing-coded that was created before the media your pairing is in. "This is so me coded!" No, it is not; the creator was not thinking about you.) I keep contemplating making a tumblr post on the theme of "that's not what 'coded' means!!"—but alas, I think this may be as unrecoverable as getting people to say "free rein" instead of "free reign."