We are experiencing the same issue on one of our sites with Download Manager Pro installed, and can verify that modifying line 339 in libs/class.Apply.php does resolve the issue, thank you Nicholas for your through analysis and solution! Another one of our clients is also using Download Manager on a much simpler site with fewer plugins and is not having the issue. When Download Manager Pro is deactivated on the site in question the logout redirect performs as expected. The site also has WooCommerce and LearnDash installed which could possibly be contributing to the issue, but not sure. Please consider implementing Nicholas’s solution, I’m sure there are others out there that are having the issue as well and haven’t noticed or taken the time to post something.
Thanks so much