OSPF over VTI is not working

I want to run OSPF over VTI interfaces using 2 x86 routers but facing some problems with connection marking mangle rules in prerouting. Topology is following

Site-1 Configuration:

IPSEC Conf:

/etc/ipsec.conf
conn Site1
  left=192.168.50.1
  right=192.168.50.2
  auto=start
  leftsubnet=0.0.0.0/0
  type=tunnel
  rightsubnet=0.0.0.0/0
  keyingtries=%forever
  leftauth=psk
  rightauth=psk
  ikelifetime=8h
  ike=aes256-sha1-modp1536
  esp=aes256-sha1
  mark=100

ipsec.secrets:

%any %any : PSK "admin123"

VTI Conf

ip tunnel add vti1 mode vti local 192.168.50.1 remote 192.168.50.2 key 100
ip link set vti1 up
ip addr add 10.100.100.1/30 dev vti1

I have also changed the sysctl.conf value for VTI interfaces

net.ipv4.conf.vti1.disable_policy=1

OSPF Conf:

interface vti1
 ip ospf mtu-ignore!
router ospf
 network 10.100.100.1/32 area 0.0.0.0
 network 192.168.10.0/24 area 0.0.0.0

By doing this I have found my tunnel is successfully established but I didn't get any point-to-point ping between my vti interfaces and OSPF neighbor is not getting up.

Then I got there are some prerouting rules appending in the mangle-Prerouting chain like this.

After flashing the rules from Prerouting ping on vti interfaces is running smoothly and OSPF neighbor is up immediately. But the pr-routing rules are appending every time when IP-Sec is initiated again. Is there any clue here on how to stop strongswan to insert the pre-routing rules in IP tables?