The BlobClient class contains in many of its methods the capability to add a Customer Provided Key for encryption, by supplying a cpk argument that must contain a CustomerProvidedEncryptionKey object. Inside those methods, the CustomerProvidedEncryptionKey is converted into a CpkInfo object, as this seems to be the object that the lower-level method wants.

However apparently the CpkInfo class was modified a while ago, and one of its attributes, encryption_algorithm, was removed, while the code in BlobClient still tries to set it. An example (though it happens several times in the file) can be seen at :

This produces warnings

encryption_algorithm is not a known attribute of class <class 'azure.storage.blob._generated.models._models_py3.CpkInfo'> and will be ignored

.... i.e. it seems that the operation does go through, though the code seems to be a leftover