We are facing the same issue:
In the last days we keep receiving alerts about "high network usage" on Meraki, e.g.:
The 20 minute usage on the XXXX - Location - appliance network from 10:00 AM to 10:20 AM CEST on Oct 11 was 119.98 GB.
Although there is no spike in traffic when checking the dashboard, the overall traffic over 2 hours is around 200GB.
The majority of the traffic is internal and is made up of CCTV cameras that are fed into the NVR through a separate VLAN, but it's not even close to 100GB / 20 minutes.
Changing the alert threshold is something I can do, but I'd rather understand the triggers to improve my monitoring.
Any ideas ?