Version 5.0.6

system/Content/Taggable.php

@@ -200,6 +200,9 @@ trait Taggable
 			$set = array( $set );
 		}
 
+		/* Weed out duplicates */
+		$set = array_unique( $set );
+
 		$insert = [];
 		foreach ( $set as $key => $tag )
 		{
@@ -346,7 +349,7 @@ trait Taggable
 					
 		if ( count( $options['autocomplete']['source'] ) )
 		{
-			$containerClass = static::$containerNodeClass;
+			$containerClass = static::$containerNodeClass ?? null;
 			$containerFieldName = static::$formLangPrefix . 'container';
 			$thisClass = get_called_class();
 			return new Text( static::$formLangPrefix . 'tags', $item ? ( $item->prefix() ? array_merge( array( 'prefix' => $item->prefix() ), $item->tags() ) : $item->tags() ) : array(), ( Settings::i()->tags_min and Settings::i()->tags_min_req ) ? ( $container ? TRUE : NULL ) : FALSE, $options, function ( $val ) use ( $container, $containerClass, $containerFieldName, $thisClass ) {
@@ -354,7 +357,7 @@ trait Taggable
 				{
 					if ( !$container )
 					{
-						if( $containerClass )
+						if( $containerClass !== null )
 						{
 							try
 							{