Hey @dallas_4094,
Great question - the collection of Adobe Stock that's available within Adobe Express for free changes over time as assets cycle in and out based on licensing, and it looks like this one did. Not a bug, but I'll be honest: Express doesn't warn you when something in an active project gets reclassified, which can then be annoying and a surprise, especially if you're used to using it! This is something we've passed along as feedback to the team internally.
Something to know: Express licenses assets at export time, not when you place them. So if you already downloaded or published your project while it was free, you're covered. If you haven't exported yet, you'd need to license it at the premium price now -- at which point swapping it for a similar free asset might be your easiest move.
Rose