SSE-C requiring blob as CustomerKey instead of base64 encoded string

While storing object in S3 s3://srprak.test/local/userdata/GXX2AM5MLP375ENM_amzn1.account.AERUZR24XTA3ISW2HGSW7P7WNVLA/B00KDSGIPK/appdata.tgz, we are encrypting it with SSE-C key.

But while we download it with the same key, it is not able to download the S3 object.

As per the documentation, https://docs.aws.amazon.com/cli/latest/reference/s3/cp.html

--sse-c-key (blob) The customer-provided encryption key to use to server-side encrypt the object in S3. If you provide this value, --sse-c must be specified as well. The key provided should not be base64 encoded.

It is asking not to send base64 encoded.

This was working earlier but it has recently started to break.

AWS COMMAND: aws s3 cp s3://srprak.test/local/userdata/GXX2AM5MLP375ENM_amzn1.account.AERUZR24XTA3ISW2HGSW7P7WNVLA/B00KDSGIPK/appdata.tgz . --sse-c AES256 --sse-c-key RG97HwycFgQ4aAa6GsFMrug32jqimm61YIyE82p+hgg= --debug

As per the github link, https://github.com/aws/aws-sdk-cpp/blob/61ab9c1dc84264a5e0f166895d64cff1a0652a11/generated/src/aws-cpp-sdk-s3/include/aws/s3/model/GetObjectRequest.h#L959 I see it still taking a string.

Can you let us know when this change was introduced?