3.8.4 —-> 3.8.5 update introduces problem

Hello,

After updating MailPoet from version 3.8.4 to 3.8.5 there is a problem:

Warning: Cannot modify header information – headers already sent by (output started at /MY_URL/wp-content/plugins/mailpoet/lib/Config/Initializer.php:295) in /MY_URL/wp-admin/includes/misc.php on line 1126

I’ve removed the URL in case of security issues.

This happens no matter which tab you select (Emails, Forms, Subscribers etc)

Let me know if you need any further info.

PHP Version: 5.6.37