Intermittent IPSEC Connection Issues with CISCO ASA

We have a situation where at two sites we receive reports that the connection is down. However, we we connect to the XG the VPN reports as UP & the LINK is green. The only way to resolve is to disconnect the VPN & re-establish it.

The logs seems to fill with IPSEC Terminated Connection between <IPADDRESS> & <IPADDRESS> Terminated - Log ID 17802

One re-established the VPN works fine again for a few days or so

1 x XG210 Firewall running  SFOS 17.1.1 MR-1

2 x CISCO ASA (different sites)

Two sites we receive reports that the connection is down. However, we we connect to the XG the VPN reports as UP & the LINK is green. 

The XG is set to Initiate the Connection

The Policy in the XG 

IKEv2

0 Key Negotiation Tries

Allow Re-keying is Selected

Phase1
KeyLife 86400
Rekey Margin 360
Randomise Reksying by 100
DH Group 2 (DH1024)
Encryption AES256
Authentication SHA1

Phase2
PFS Group (none)
Key Life 28800
Encryption AES256
Authentication SHA1

Dead Peer Detection is selected & checks every 30 secs & will wait for up to 120 secs when the Peer is unreachable


Any issues or suggestions on how we could resolve this?

Thanks