With JomSocial 3.1 onwards, the dashboard counters are implemented in JomSocial Backend Panel. These counters hold various statistical data about your community and are available to all admins in main control panel view.
Is members counter wrong?
No! By design members counter will only show those users that have at least one (1) JomSocial User Point
User points are assigned on every individual action available in JomSocial and it is the easy way to recognise how many users actually used your community.