Steps to reproduce the issue

Create 3 articles (Test article 1, Test article 2, Test article 3)
Create 3 Tags in the Tags Component (Tag 1, Tag 2, Tag 3)
Add to all the three articles all three tags
Create a menu item of the type "Compact list of tagged items"
Select in the menu item all the three tags in the Tag field
Select content type Article.

Access the menu item and the warning "Notice: Array to string conversion in C:\xampp\htdocs\joomla\libraries\joomla\filter\input.php on line 201" should be there.

Expected result

There should be no Notice warning

Actual result

A warning "Notice: Array to string conversion in C:\xampp\htdocs\joomla\libraries\joomla\filter\input.php on line 201"
The list of the articles which have the corresponding tags

System information (as much as possible)

PHP versie 5.6.9
Webserver Apache
WebServer naar PHP interface litespeed
Joomla! versie Joomla! 3.4.3 Stable [ Ember ] 2-July-2015 16:00 GMT
Joomla! Platform versie Joomla Platform 13.1.0 Stable [ Curiosity ] 24-Apr-2013 00:00 GMT
Gebruikersagent Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.132 Safari/537.36

Additional comments