I see what you mean! I traced this out and it looks like the backslashes are in place until this plugin hands off the content to bbPress. They are ultimately taken off when the new topic is made, when WP runs
stripslashes on the content.
addslashes before sending the content along, but I want to do some testing and make sure that doesn't cause any issues. In the meantime, you can put a snippet like the following in your theme's
functions.php file to accomplish the same thing:
add_filter( 'bbppt_topic_content', 'addslashes' );
Let me know how this works for you!