There are several tasks that are not doing well. Some youtube videos that cannot be viewed because the video itself is not found. There was also a Google+ task that cannot be confirmed. Even if the task is already completed the error when you confirm will tell you that the task is not yet completed.
yeah, I suffered the same issues with some tasks, but don't think they were with DENT tokens
just saw 4 new YouTube like tasks online
tho since there is limitation in the number of users to complete is, you have to be quite fast