When opening some loot box there's always a chance for extra stars on top of the guarantee or randomly receiving darwinium cubes. These are not mentioned in the description. Screenshots attached as examples. When pulling a black hole the description says 100% for 3 stars which is true. But you can pull more. I've even pulled 6 stars, I just didn't take a screenshot.
As far as I know this isn't new. But I feel like they should at least mention there's a chance you can get bonus stars or darwinium cubes. I also suppose this should extend to geodes purchased in Mesozoic valley, but I haven't played that simulation in a long time.