One or more users have used Workforce Analytics / Planning without appearing in the Site Statistics Report for the period afterwards.
SAP SuccessFactors Workforce Analytics
A user's entire session is recorded in the log upon logout. If a user simply closes the browser window there is no official logout and the session may not be recorded at all. Sometimes it will be if the timeout is recorded as a logout, but do not depend upon this.
Advise your users to log out properly, using a logout link in a Simple Text component (LOGOUT is a Dynamic Link Token; see the component editor).
KBA , LOD-SF-WFA , Workforce Analytics & Planning , Problem