Fixes the error like below that is occurring when you load the author rss feed (post type query var is empty) or when the post type query var is an array.
PHP Fatal error: Uncaught TypeError: Illegal offset type in /site/wp-includes/post.php:2285
Stack trace:
#0 /site/wp-content/plugins/pronamic-events/classes/class-feed-module.php(33): post_type_supports(Array, 'pronamic_event')
#1 /site/wp-includes/class-wp-hook.php(324): Pronamic_Events_FeedModule->rss2_ns('')
Fixes the error like below that is occurring when you load the author rss feed (post type query var is empty) or when the post type query var is an array.