gRPC UpdateObject not clearing Object encryption_config when field empty in request

When making an update object request and leaving the encryption_config empty, the object's encryption_config is not being cleared, and is incorrectly returning the existing encryption_config.

Example:
UpdateObject request:
bucket {
name: "projects/_/buckets/testbucket"
encryption {
}
}
update_mask {
paths: "encryption"
}

The above request should clear the config and return the cleared encryption_config as in the bucket below.

Expected response bucket:
blob_v2_bucket {
metadata_generation: 3
project: "projects/123456789"
location: "EU"
storage_class: "STANDARD"
encryption_config {
}
}

However, it is instead returning the existing encryption_config without clearing the fields as in the bucket below.

Actual response bucket:
blob_v2_bucket {
metadata_generation: 3
project: "projects/123456789"
location: "EU"
storage_class: "STANDARD"
encryption_config {
default_kms_key_name: "a/default/test/key"
}
}