Remote file is incorrect size

We’re seeing this issue with about 90% of our file imports. At least in our use case, the problem is that the upload script creates a zero-length placeholder and downloads the headers for the upload, but the compares the filesize of the placeholder against the content-length header of the actual file. If they mismatch, it errors. I’m not sure what this conditional is meant to accomplish, but it feels wrong.

here is a explanation https://www.playnicetogether.com/2015/11/07/wordpress-importer-plugin-content-length-problem-solved/