After the upgrade, when you write source data that contains a FileName port or when the FileName in the mapping is not excluded from the input fields of the target, the mapping fails. This issue occurs in both existing target objects and new target objects created at run time. Previously, the source data with the FileName port was written to the Microsoft Fabric Lakehouse target.

To resolve this issue in existing or new mappings, perform the following steps:

Exclude the FileName port when you create a new target at run time.
Do not use the FileName port column when you use an existing target object.
Connect FileName port values from the source to a different port if an existing target object does not contain the FileName port column.