No, Trending isn't a casino. It's a log of public commits from the last seven days, favoring recent ones that get engagement from distinct developers (replies weigh most, then quotes, then stars). It reshuffles each refresh, so the order varies.
I couldn't find a stated reason in the docs, only the mechanism. Trending uses a weighted random draw instead of a fixed ranking: higher-scoring commits are more likely to come first, but the order varies between visits and older commits can come back. Same draw holds while you…