Does poker tracking software like HEM generates HUD states about my current opponents at the table based of current game, or are the states generated from database(all the game I played with those opponents)? Because some opponents for example can have low VP$IP based on on my longterm database records but can change style of their play in current session. So I could think that they are playing tight but they are actually loose in current game.
Typically these programs will generate their stats based on a long term collection to maximize the sample-size (and thus overall accuracy) driving the information. All decent HUD programs will include the option of displaying how many hands the information is based on, which can lead you to determine whether it is long-term or current-session. In many of them, you can also configure specific filters so that it only shows hands from a given timeframe, or with a certain range of numbers of players at the table.
If your program of choice lacks some of those options, you may want to consider switching to a new database periodically to avoid relying on outdated information. That said, generally more hands behind the information you are using leads to better accuracy and thus better results.