Jira imports a date by removing 233 or 236 days

[Venky Krishnamurthy]

I am seeing some peculiar behavior with Jira imports recently.  I have two date pickers, custom fields. When I am bulk importing the data, most of the "Dates" are imported as-is. However, with respect to two specific dates, Jira seems to add it's own days and import. 

For ex: if the date is  19th Aug 2022, it updates as 26th Dec 2021.  If the date is 21st Aug 1990, it updates as 31st Dec 1989

There was one exception, with 2nd Jan 2000, it updated as 26th Dec 1999

I am unsure what's happening here.  Can someone decipher it for me please?

I also realised, sometimes, it just sticks to 26th Dec 2021. I don't know where this date is being picked. 

[Brant Schroeder]

@Venky Krishnamurthy Welcome to the Atlassian community

Is there anything in the import logs that you are seeing?  When you review the import is the transformation already happening?