Arguments are incorrectly fetched for defaulted displays

I had a quick glance of your code, coming from comment 1 here: #865458: Allow views arguments as cache keys.

You are getting the arguments for a display incorrectly:

$view_arguments = $view->display_handler->options['arguments'];

This line only works on the default display, or a display whose arguments have been overridden, instead you want to use:

$view_arguments = $view->display_handler->get_option('arguments');

Which will fall through if the section is defaulted.