Hey Jonas,
I’ve studied the code and found the reason for the bug: the “allow_url_fopen” parameter in your server’s php.ini settings has been disabled, which led to the function that governs the fixed header generating an internal error and terminating. Haven’t taken this possibility into account earlier, thanks for bringing this up! Server-side restrictions should not impede the work of vital theme elements, so after some experimenting I’ve prepared a fix that also works when the “allow_url_fopen” has been turned off – please download this archive, unzip it, and upload the resulting files into the theme folder (/wp-content/themes/Shogun/), replacing the existing files. Let me know if the fix works!
Sincerely,
Andrii / Satori Studio