If a joined layer is used as source, Data Assistant does not append it to the target. It seems to work correctly in the dla.gdb feature class, but when arcpy.Append_management() is called, it does not append to target. The Result object from this append management call contains the following message log.
...and so on for the length of the source dataset.
Determined the issue. It is not actually a problem with join layers, but an issue with trying to append null onto a field that does not accept null values. Will create a new issue on this
If a joined layer is used as source, Data Assistant does not append it to the target. It seems to work correctly in the dla.gdb feature class, but when arcpy.Append_management() is called, it does not append to target. The Result object from this append management call contains the following message log.
...and so on for the length of the source dataset.