Steps to reproduce:

• creation of a network map for site (three buildings)
• creation of map tree that links to the network map
• unreachability alarm on device on building 'Palazzo D' (ICMP Template)
• average number of alarms is increased by one (both hight and average allarm)

Result:

• wrong average number of alarms, is increased by one
  See screenshot...

Expected:

• clone map tree
• edit network map by removing building with device in alarm
• number of average alarms return correct

See screenshot...