Symptoms
Assume that you have a PolyBase external table in SQL Server 2019 with a column of type TIME pointing to an Oracle, Mongo DB, Teradata, or Generic ODBC external data source. You try to read from the external table's TIME column. In this scenario, you notice that null values in the column are replaced with incorrect data.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Resolution
This issue is fixed in the following cumulative update for SQL Server:
Each new cumulative update for SQL Server contains all the hotfixes and security fixes that were in the previous build. We recommend that you install the latest build for your version of SQL Server:
References
Learn about the terminology that Microsoft uses to describe software updates.
The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.