Regardless of why it's happening, it is very clearly a bug since it is presenting the wrong information.  We can choose to ignore the bug since it appears the source has been identified, but it is obviously not properly recording time logged in.  I don't think these stats matter, nor do I care if it's correct.  Call a spade a spade though.  This is most definitely a bug.  It appears it's been a known bug for a while, so it is either low priority and very far down the todo list, or nobody in a position to correct the bug cares.  Take your pick.