I had a site I was running with a block-based/FSE theme on WP v.6.1.1. In functions.php, I was loading my theme stylesheet in the Gutenberg editor using the following:

function dnl_theme_add_editor_styles() {
  add_editor_style();
}

add_action( 'after_setup_theme', 'dnl_theme_add_editor_styles' );

This worked perfectly well (editor-style.css loaded in Gutenberg) until I upgraded to WordPress 6.2. After that, the stylesheet stopped getting loaded in the editor. I tried loading style.css using add_editor_style like so:

function dnl_theme_add_editor_styles() {
  add_editor_style( 'style.css' );
}

I also tried calling add_theme_support first, e.g.:

function dnl_theme_add_editor_styles() {
  add_theme_support( 'wp-block-styles' );
  add_editor_style();
}

But none of that helped.

Has anyone else noticed this behavior after upgrading? Does anyone know why this would be happening? I looked at the source code for add_editor_style in wp-includes/theme.php and didn’t see any changes there since 6.1.1.