Data flow is giving error as lease create a master key in the database or open the master key in the session before performing this operation. cut copy activity is getting succeded

I tried to copy data from Synapse to Synapse using staging but initially I am getting same error as you but after running copy activity for the same and its successful execution the data flow is also executed successfully.

Thread link for the issue:
https://stackoverflow.com/questions/76519702/in-adf-extracting-data-using-ingest-feature-works-fine-but-cannot-extract-data