RSPAN FortiAP port on managed FortiSwitch brings FortiAP down

[masterofdesaster-01]

Hi,

when enabling RSPAN on a managed FortiSwitch port with a FortiAP connected the FortiAP will be unavailable after a short time until RSPAN is disabled again. Packets can be captured on the sniffer VLAN 4092 on FortiGate. While RSPAN is active we noticed that ICMP Ping to the FortiAP management IP receives duplicate answers.

Is it possible the FortiAP communication with FortiGate WiFi Controller is impacted because Fortigate receives AP communication on VLAN 4092 as well and interprets it?

We have a TAC case open but as there were som sync errors while testing ERSPAN the current recommendation is to upgrade FortiOS to 7.0.9. Currently we are running FortiOS 6.4.11, FortiSwitchOS 7.0.5 and FortiAP 7.0 Build 34

Or is somebody with a similar setup able to reproduce it?

[masterofdesaster-01]

Just tested the behavior when changing the VRF ID of FortiLink VLAN4092 interface from "0" to "1" so that it's isolated. FortiAP stays available! Seems that verifies my assumption that FortiGate receives the mirrored packets on VLAN4092 and doesn't ignore them if it's in the same VRF as the production VLAN used for the APs.