From an Esri email about AGOL update coming in October 2025:
Action Required If You Use the Additem Operation
When using automated scripts or workflows to add content to ArcGIS Online, such as from third-party software, it is now essential to include a valid type value. Without a valid type value, the addItem operation will fail. Therefore, ensure that your scripts or workflows are configured to apply type values.
From an Esri email about AGOL update coming in October 2025: