"Now that my tax return is being processed again,..."
The reprocessing is the most likely reason for the new IRS request. But whatever their reason might be, you should do what they ask so that your return won't be automatically rejected in the reprocessing.
TurboTax has a help article on this topic:
https://turbotax.intuit.com/tax-tips/security/tips-for-handling-identity-verification-requests-from-...
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
