Incidentally, this issue is also reported on the following parallel threads:
https://ttlc.intuit.com/community/taxes/discussion/form-2210-ty-2021-error/00/2492801
https://ttlc.intuit.com/community/taxes/discussion/error-in-form-2210-turbotax-2021/00/2490719
https://ttlc.intuit.com/community/taxes/discussion/form-2210/00/2494794
https://ttlc.intuit.com/community/taxes/discussion/2021-federal-form-2210/00/2489956
https://ttlc.intuit.com/community/tax-credits-deductions/discussion/two-errors-on-forms-2210-2210ai-...
Including them here for reference.
