If you transfer one or more users from another server, please make sure that UID_MIN value in /etc/login.defs file is lower than the UID for the transferred user(s).
For example, if you transfer accounts from an old server to a new one, and on the old server accounts have had UIDs below 1000, on the new server with UID_MIN 1000 the statistics won't be collected for transferred accounts, and those users won't be visible in LVE Manager as well.