diff --git a/wp-admin/includes/post.php b/wp-admin/includes/post.php
index aba113c7a5..f76f16e625 100644
--- a/wp-admin/includes/post.php
+++ b/wp-admin/includes/post.php
@@ -2045,6 +2045,11 @@ function use_block_editor_for_post( $post ) {
 		return false;
 	}
 
+	// The posts page can't be edited in the block editor.
+	if ( absint( get_option( 'page_for_posts' ) ) === $post->ID && empty( $post->post_content ) ) {
+		return false;
+	}
+
 	$use_block_editor = use_block_editor_for_post_type( $post->post_type );
 
 	/**
diff --git a/wp-includes/blocks.php b/wp-includes/blocks.php
index e817286ff7..fe83ef7750 100644
--- a/wp-includes/blocks.php
+++ b/wp-includes/blocks.php
@@ -222,7 +222,7 @@ function do_blocks( $content ) {
  */
 function _restore_wpautop_hook( $content ) {
 	global $wp_filter;
-	$current_priority = $wp_filter['the_content']->current_priority();
+	$current_priority = has_filter( 'the_content', '_restore_wpautop_hook' );
 
 	add_filter( 'the_content', 'wpautop', $current_priority - 1 );
 	remove_filter( 'the_content', '_restore_wpautop_hook', $current_priority );
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 4370a3dabe..6e8b1a288d 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44241';
+$wp_version = '5.1-alpha-44242';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.