I have experienced this in the past, my theory is that status updates with a lot of tags do not appear on the front page as the BB code associated with tagging the users surpasses the character limit for status updates. It is a loophole that allows you to technically (with BB coding applied) post a status with more than 140 characters but it will not appear on the front page as a result.
To recreate this, try making a status update from your profile page that is 135-139 characters but include a user tag as well. Once you post this status, if my theory is correct, be able to see it on your profile but not on the front page of the forums.
Apologies for the late reply. I hope this makes (some) sense.