FortiAP-W2 models may experience bootup failure during federated upgrade process if they are powered by a managed FortiSwitch's PoE port
Disable the federated upgrade feature if you have FortiAP-W2 devices that are exclusively powered by a PoE port from a FortiGate or FortiSwitch.
The federated upgrade feature starts the upgrades of managed FortiSwitch and FortiAP devices at approximately the same time. Some FortiAP-W2 devices take a longer time to upgrade than the FortiSwitch devices. When the FortiSwitch finishes upgrading, it reboots, and can disrupt the PoE power to the FortiAP devices. If a FortiAP device is still upgrading when the power is disrupted, it can cause the FortiAP device to experience a bootup failure.
Manually triggering federated upgrade can cause this issue. Starting in 7.2.8, automatic firmware upgrade will no longer trigger FortiSwitch and FortiAP to be upgraded.
For more information about federated upgrade, see Upgrading Fabric or managed devices.