Resolves #6412.

Proposed Changes

In certain scenarios such as custom queries, the global $post variable may not be set or may not be an instance of WP_Post. This can occur if the_content is applied outside the main loop or if other plugins/themes manipulate the global $post variable.

To be safe, switching to using get_post instead.

Testing Instructions

N/A. I wasn't able to reproduce, but the code now does an extra check that $post is actually an instance of WP_Post before trying to access the ID property.

Pre-Merge Checklist

• PR title and description contain sufficient detail and accurately describe the changes
• Adheres to coding standards (PHP, JavaScript, CSS, HTML)
• All strings are translatable (without concatenation, handles plurals)
• Follows our naming conventions (P6rkRX-4oA-p2)
• Hooks (p6rkRX-1uS-p2) and functions are documented
• New UIs are responsive and use a mobile-first approach
• Code is tested on the minimum supported PHP and WordPress versions