The top few Challenges loaded in the Discover Challenges tab are current, but as you scroll the list doesn't match what you'll see on web. Sometimes if you tap a few of the Challenges in that list, it will provide an error because that Challenge has already closed.
Here's a screenshot a user (900fde56-66c9-4ea0-9b6b-25e73a249790) provided marking some of the Challenges that seem stuck in the discover list:
The top few Challenges loaded in the Discover Challenges tab are current, but as you scroll the list doesn't match what you'll see on web. Sometimes if you tap a few of the Challenges in that list, it will provide an error because that Challenge has already closed.
Here's a screenshot a user (900fde56-66c9-4ea0-9b6b-25e73a249790) provided marking some of the Challenges that seem stuck in the discover list: