SDWAN: IPsec Aggregation under NAT is not seen

Hello,

IPsec aggregation I/F is not seen when I try to input it as SDWAN member.

Here is my environment.

       (wan1) --- NAT router1 --- (wan2)

FG1                                                     FG2

       (wan2) --- NAT router2 --- (wan2)

At FG1, as VPN tunnel, vpn1_1 and vpn1_2 are created

And AGGnat I/F is created as aggregation of the both.

At FG2, the situation is similar.

In VPN tunnel, AGGnat I/F is up. However, this I/F is not seen as SDWAN member.

How can I solve?

Any comments are appreciated.