Check to see if your post count is lost, and many times the moderator deletes some old invalid post.
moderators delete old topics, I lost ~30 messages, why I must post 31 massages? the rules say that need minimum 1 message.
sem is based on the total amount of post last week, that is, if the total amount of post this week is less than that of last week, then you can't get the bounty.