yours is a strange case, i double checked.
i download a tar file generated by HFS, and path delimiter is "/".
indeed, i clearly see the instruction replacing "\" with "/" at tar creation, so no wonder.
could please provide a tar file so i can have a look at it?
please, just few files, and few kilobytes. if you can try to attach it here on the forum, or send it to support@rejetto.com
thanks