Turbotax has nothing to do with how or why the IRS selects certain returns for verification. They may be looking at many factors, their methods are secret. We have a good idea that returns may be selected if you had an address change; if you are requesting a large refund on a debit card; if your bank account for direct deposit changed; or if your employer did not submit the employer copy of your W-2 to the IRS. There may be other reasons that are not disclosed. The whole point is to protect you from identity theft.
https://www.irs.gov/individuals/understanding-your-5071c-letter