1. In the WordPress admin dashboard, when switching from Code to Visual, the switch fails and the console throws an error: Uncaught TypeError: _.pluck is not a function. See Figure 1.

2. This indicates that the code uses _.pluck(), but the currently loaded version of Underscore.js has already removed this method. However, some outdated WordPress plugins, themes, or core JS files still call _.pluck(), causing the error.
3. Ultimately, I had to disable the Classic Editor and enable Gutenberg. See Figure 2.

