Is this AD Sync ?
if yes check with duplicate entries if any in sepm example if there was any machine and no longer now the user still with ad and not removed will show in sepm as one license count and then overdeployed stauts .so any entry which is no longer in the ad remove it and wait for 24 hrs
2nd option :
Go to home tab in the top right select preferences tab go to last tab change the date format from ddmmyy to other then restart sepm service
change the preference to dd mm yy again and check