Put it this way...On Check Point, unlike say Cisco or Fortinet, as there is VIP involved, you have to ensure that all the routes and config matches on backup member, as it wont replicate automatically to standby when you make a change on the active. So, if that cable is unplugged it would make sense why it fails, as Im sure if you were to run command ip r g 8.8.8.8, it would not be reachable.
You can also run below (example from my lab)
[Expert@quantum-firewall:0]# ip r l
default via 172.16.10.103 dev eth0 proto 7
4.205.75.119 via 173.46.3.216 dev eth3 proto 7
10.1.0.0/16 via 169.254.21.1 dev vpnt1 proto 7
169.254.21.1 dev vpnt1 proto kernel scope link src 169.254.21.2
172.16.10.0/24 dev eth0 proto kernel scope link src 172.16.10.205
173.46.3.208/28 dev eth3 proto kernel scope link src 173.46.3.220
192.168.205.0/24 dev eth2 proto kernel scope link src 192.168.205.205
205.195.249.0/24 dev eth1 proto kernel scope link src 205.195.249.1
[Expert@quantum-firewall:0]#
Andy