JS error on post.php admin interface

Hello,

The latest updates has introduced a JS error preventing post save on post admin edit pages.

The problem seems to come from wp-content\plugins\mailin\js\post-editor.bundle.js at var e = n.getCurrentPost();. At this point if the editor is not Gutenberg, n is undefined. Therefore it trigger a JS error preventing later JS interactions with the page.

Could you please provide a fix for this problem ?

Thanks in advance for your answer.