VXLAN over IPSEC - can't add member to the switch-interface

is it working configuration for VM https://docs.fortinet.com/document/fortigate/6.2.0/cookbook/821119/vxlan-over-ipsec-tunnel ?

I have tried it on a pair of FGT_VM64-v6-build0866-FORTINET. Everything is OK except the last step 4 with "set member" command.

It is impossible to add a port to the switch if it mentioned previously somewhere in configuration.

Moreover according to the Cookbook 

"The ports that you include must not have any link or relation to any other aspect of the FortiGate unit, such as

DHCP servers, security policies, and so on."

It is impossible not in CLI not in GUI.