terraform S3 policy issue

Even after terraform apply, terraform plan still sees policy changes:

    ~ aws_s3_bucket.bucketname
    policy: "{\"Statement\":[{\"Action\":\"s3:PutObject\",\"Effect\":\"Allow\",\"Principal\":{\"AWS\":\"arn:aws:iam::xxxxx:root\"},\"Resource\":\"arn:aws:s3:::bucketname/*\",\"Sid\":\"\"}],\"Version\":\"2012-10-17\"}" => "{\"Statement\":[{\"Action\":\"s3:PutObject\",\"Effect\":\"Allow\",\"Principal\":{\"AWS\":\"arn:aws:iam:xxxx:root\"},\"Resource\":\"arn:aws:s3:::bucketname/*\"}],\"Version\":\"2012-10-17\"}"
    

The policy file I’m specifying doesn’t have a SID, because a) I don’t want to hardcode that (and it should be optional), and b) it may be applied to multiple buckets.

This is the policy file:

    {
      "Version": "2012-10-17",
      "Statement": [
        {
          "Effect": "Allow",
          "Principal": {
            "AWS": "arn:aws:iam::xxxxx:root"
         },
          "Action": "s3:PutObject",
          "Resource": "arn:aws:s3:::bucketname/*"
        }
      ]
    }



Is there any way around this besides telling terraform to ignore policy changes?