As Opus 17 suggests, absent the contribution that was intended to be made for 2022 mistakenly being made for 2023 (with the traditional IRA custodian recording it as a 2023 contribution by default), this response from the IRS would result from either filing an incorrect 2023 Form 8606 or failing to file a 2022 Form 8606 claiming a nondeductible traditional IRA contribution for 2022 (or both).
