do not use attribute inside custom block form

packages/forms/src/Components/RichEditor.php

@@ -603,6 +603,13 @@ class RichEditor extends Field implements Contracts\CanBeLengthConstrained
 
     public function getContentAttribute(): ?RichContentAttribute
     {
+        // Do not read content attributes from the model when the rich editor is nested
+        // inside a custom block action modal, since the content attribute should only
+        // be used to configure the parent rich editor.
+        if ($this->getRootContainer()->getOperation() === CustomBlockAction::NAME) {
+            return null;
+        }
+
         $model = $this->getModelInstance();
 
         if (! ($model instanceof HasRichContent)) {

packages/forms/src/Components/RichEditor/Actions/CustomBlockAction.php

@@ -9,9 +9,11 @@ use Filament\Support\Enums\Width;
 
 class CustomBlockAction
 {
+    public const NAME = 'customBlock';
+
     public static function make(): Action
     {
-        return Action::make('customBlock')
+        return Action::make(static::NAME)
             ->fillForm(fn (array $arguments): array => $arguments['config'] ?? [])
             ->modalHeading(function (array $arguments, RichEditor $component): ?string {
                 $block = $component->getCustomBlock($arguments['id']);