After upgrading 1570R firewalls from R81.10.05 b254 to R81.10.08 b711 , recommended by Check Point, we experienced outages on VPNs with third-party entities, primarily Cisco.
We noticed the IKEv2 IDr field transitioned from containing the IP address to now containing the hostname of the gateway. The problem was resolved by downgrading, and a comparison of the two "legacy_ikev2.xmll" files revealed the difference. In our case, the remote end was not able to change the field as this was a mandatory requirement.
https://support.checkpoint.com/results/sk/sk33822 scenario 1 does not seems to be applicable on spark devices.
TAC case is open, so normally, in 4 months, we will have a solution ! Keep this in mind when upgrading to this version when having VPN's with 3th parties .