I was out shopping on Saturday and went to Wal-Mart, where I bought the last remaining items I needed for Halloween candy. While I was there, I picked up another Crush Rainbow Pack of pop. I purposefully stuck a can of cream soda from the new pack into the fridge to chill. I opened it the next day, and it was indeed the usual red color.
Similarities: Crush rainbow pack, 24 cans, all the same flavors. Identical can design and ingredients listing.
Differences: Old can had a gold top and "Quebec" written on it with the recycling message. New can had a silver top and did not say "Quebec."
Additional info: From visiting my brother in Montreal, I know that they do not color their margarine in Quebec. It is actually illegal to color margarine to look like butter in Quebec -- the dairy industry believes that colored margarine would hurt butter sales. Read more about that issue here.
Conclusion: Perhaps cans of Crush Cream Soda are not colored if they are manufactured in Quebec.
This is somewhat of a stretch, because the colored margarine issue in Quebec is strictly a dairy industry issue. However, it's odd that both margarine and Crush cream soda manufactured in Quebec are missing color. Another piece of the puzzle.