Forti does not send "sa delete" when bringing down tunnel

[Pattex]

Hi,

we have 2 Forti sites with tunnel against same partner gateway. 1 one site the partner receives properly a "sa delete" when I bring down the tunnel. On the other site not.

Overall both tunnel are working properly. Just the issue is, if for i.e. DPD the tunnel goes down the partner will no see it. So may keep up the Phase1 still, which makes it impossible to get tunnel up again. Any idea why one of our gateways sends the SA delete and the other not

thx in advance

EDIT: I forgot, version 6.0.x

[emnoc]

Did you do any "diag debug app ike 10 " and is this ikev1 or ikev2? What event are you expecting to cause or generate the ipsec-SA delete?

if you down a ipsec-SA do you see a delete 

e.g 

diag vpn tunnel down vpn3

Ken Felix