Ticket #33466: 33466.2.patch

src/wp-includes/formatting.php

@@ -572 +572 @@
         // Optionally insert line breaks.
         if ( $br ) {
                 // Replace newlines that shouldn't be touched with a placeholder.
-                $pee = preg_replace_callback('/<(script|style).*?<\/\\1>/s', '_autop_newline_preservation_helper', $pee);
+                $pee = preg_replace_callback('/<(script|style|textarea).*?<\/\\1>/s', '_autop_newline_preservation_helper', $pee);
 
                 // Normalize <br>
                 $pee = str_replace( array( '<br>', '<br/>' ), '<br />', $pee );