As of 8th February Google Docs access is in beta. 

As Google Docs for free users has no formal API by Google it is not possible to ascertain the file size when a first time sync is done. The file will be available but will show as '0' bytes. After the file has been downloaded once the file size will then show.

This can lead to an issue if downloading these file via a client tool for the first time. It can result in the download failing, but if the download is attempted again then the file should download fine and will be fine in the future.