R2 file does not generate md5 check code

Hi, I am using the sync parameter of rclone tool to upload files to R2 bucket, I found that some files uploaded at the same time have md5 check digit while some others don’t have md5 check digit, which makes there is no way for us to check whether the files are normal or not.

Example of rclone sync command synchronization: ./rclone-v1.64.1-linux-amd64/rclone sync src dest -P --s3-upload-concurrency=32 --transfers=32 --config=“. /rclone-v1.64.1-linux-a
md64/rclone.conf”`

r2 file metadata