Index: src/js/_enqueues/admin/inline-edit-post.js
===================================================================
--- src/js/_enqueues/admin/inline-edit-post.js	(revision 49702)
+++ src/js/_enqueues/admin/inline-edit-post.js	(working copy)
@@ -329,6 +329,11 @@
 				textarea = $('textarea.tax_input_' + taxname, editRow),
 				comma = wp.i18n._x( ',', 'tag delimiter' ).trim();
 
+			// Ensure the textarea exists.
+			if ( ! textarea.length ) {
+				return;
+			}
+
 			terms.find( 'img' ).replaceWith( function() { return this.alt; } );
 			terms = terms.text();
 
Index: src/js/_enqueues/admin/tags-suggest.js
===================================================================
--- src/js/_enqueues/admin/tags-suggest.js	(revision 49702)
+++ src/js/_enqueues/admin/tags-suggest.js	(working copy)
@@ -38,6 +38,11 @@
 		var last;
 		var $element = $( this );
 
+		// Do not initialize if the element doesn't exist.
+		if ( ! $element.length ) {
+			return;
+		}
+
 		options = options || {};
 
 		var taxonomy = options.taxonomy || $element.attr( 'data-wp-taxonomy' ) || 'post_tag';
@@ -146,14 +151,19 @@
 
 		$element.on( 'keydown', function() {
 			$element.removeAttr( 'aria-activedescendant' );
-		} )
-		.autocomplete( options )
-		.autocomplete( 'instance' )._renderItem = function( ul, item ) {
-			return $( '<li role="option" id="wp-tags-autocomplete-' + item.id + '">' )
-				.text( item.name )
-				.appendTo( ul );
-		};
+		} );
 
+		$element.autocomplete( options );
+
+		// Ensure the autocomplete instance exists.
+		if ( $element.autocomplete( 'instance' ) ) {
+			$element.autocomplete( 'instance' )._renderItem = function( ul, item ) {
+				return $( '<li role="option" id="wp-tags-autocomplete-' + item.id + '">' )
+					.text( item.name )
+					.appendTo( ul );
+			};
+		}
+
 		$element.attr( {
 			'role': 'combobox',
 			'aria-autocomplete': 'list',