WXR export is breaking when importing in to WordPress

Hi!

I just tried exporting comments from CommentGraph to the WXR format.

When I go to import them into WordPress I get the following error for each post with a comment:

Failed to import author . Their posts will be attributed to the current user.

Warning: checkdate() expects parameter 1 to be integer, string given in /var/site/public_html/wp-includes/functions.php on line 6414

Failed to import Post “Hello World”

Here is a screenshot: https://share.getcloudapp.com/mXuydeZD

Here is the exported content: https://share.getcloudapp.com/d5uEro8o

Do you have any suggestions on how we can fix the export so it imports the comments into WordPress correctly?

Thanks!