Refer to the exhibit.

In a Fortinet Security Fabric, logs from downstream devices can be sent to FortiAnalyzer through the root FortiGate. This is why all the logs have the same source IP address (the root FortiGate). The root FortiGate aggregates and forwards the logs from all downstream devices, so the source IP in the log capture will appear to be from the root FortiGate itself, even though the logs originate from multiple devices within the fabric.