Attempting to edit the default single template of a post type leads to a page hanging with errors: "Fatal error: Maximum execution time exceeded" in specific plugin files.
Solution:
The issue appears related to execution time limits, potentially within Toolset Blocks. Start by increasing the PHP maximum execution time to troubleshoot. Additionally, duplicating the content template via "WordPress Dashboard > Toolset > Content Templates" worked correctly and allowed for editing. Disable unnecessary plugins and custom code to isolate conflicts.