Strange text on the page

i have same problem too
any new info on removing this text? for me its showing on first featured article like in first post

Try to find "_:default" in your template files and delete it. You can do it easily with total commander if you are using Windows. Command> Search> Find Text, and find every file that contains that part("_:default"). It also have ftp option.

do i need delete that file, word _:default or string?
PS. tried to do all of them and still showing in first page, first blog item _:default
it finded in these files \modules\mod_tags_popular\mod_tags_popular.xml and
\plugins\system\nnframework\helpers\helper.php

Try deleting just that string, any change?