When voiding essentia via a Storage Bus -> Void Jar, the Essentia terminal will report the essentia is still being stored.
This issue is due to the way the ME network updates. The storage bus claims to have stored all of the essentia, when in reality it is simply voiding it, however the network still believes it has been stored and sends amount updates the the terminal.
If you refresh the terminal, close and reopen it, the correct values will be displayed.