ESPP Offset Generates a W2

My former employer generated a 2024 W2 for ESPP "offset" which I had already paid taxes on.  I sold stock but I have not worked there in two years.  Now there is a tax event with the IRS for something I already paid the IRS for. 

Yes, I asked my former company this question but please understand that these people simply go through the process and really don't know the answers.

I have worked for other companies that have an ESPP program and have never had a subsequent tax event.  Any help is greatly appreciated.