Reporting previous year HSA by Employer

[JC1991]

I was enrolled in an HSA HDPD health insurance plan through my employer in the year 2022. The employer was supposed to credit $1000 to my HSA for completing some qualified medical activities.
I underwent the healthcare activities at the end of the year (Between Oct-Dec 2022) and but the employer was unable to credit the amount in my HSA account in 2022 due to processing delays. I completed the activities in time and was eligible for $1000.
I enrolled in a PPO (Non HSA) health plan for the year 2023 through my employer. I was told by my employer that since I moved to a Non HSA plan, they can't credit my account with last year's HSA credit of $1000.
Can the employer credit my account (before the tax deadline in April 2023) with the HSA credit from last year that they missed, even though I am not in an HSA plan? If yes, what is the process?

[rjs]

IRS Publication 969 says the following.

"Your employer can make contributions to your HSA from January 1, 2023, through April 15, 2023, that are allocated to 2022."

Based on that, it appears that they could have made the contribution for 2022 until April 15, 2023, but it's too late for them to make it now.

[dmertz]

If you are in a federally declared disaster area that has had the regular filing deadline for the 2022 tax return changed to October 16, 2023, the deadline for making an HSA contribution for 2022 is October 16, 2023.