Duplicate database leaves orphan archivelog files
The duplicate database ... from active database is designed to work without any existing backup.
I would expect Oracle to clean up the archivelogs which were used during the clone process.

So I would say this is an unexpected behavior. Try to log a Service Request at Oracle.

I cannot recall if I had to clean up archivelogs after a clone processes. Well, I can say that I never did delete archivelogs after a db clone because I did not check for any. I rarely clone from active database. I normally clone from backup location without a connection to the primary database. I somehow prefer that.

As workaround I would delete them with a script afterwards.