Tax Topic 152 references that your return might need additional review and could take more than the usual 21 days. This doesn't mean that there's anything wrong with your return, or that there's anything missing. For more information regarding this topic, visit the link below
Tax Topic 152: Will I Still Get My Tax Refund?
Keep in mind, once your return is filed, TurboTax has no control over the processing of your return or the release of your refund.
Here are a couple FAQs to track your refund:
When will I get my federal tax refund?
How do I track my state refund?
Why does Where's My Refund say "approved" but TurboTax still says "accepted"?
Why do some refunds take longer than others?
What if my IRS refund is taking longer than 21 days?