Fortigate not responding to specific IP but can ping it

Hi,

I'm sure this is something I'm overlooking but it does have me a little confused. My Fortigates are still in a lab setting set to roll out to production in the coming weeks.

Currently I have two Fortigates with private IP on WAN ports

192.168.2.1 Fortigate - > Cisco Switch 192.168.2.2

192.168.6.1 Fortigate -> Cisco Switch 192.168.6.2

192.168.2.1 can ping 192.168.6.1

192.168.6.1 cannot ping 192.168.2.1 but 192.168.6.2 can ping this IP. 

Monitoring the interface on the 192.168.2.1 firewall. When everything other than 192.168.6.1 pings - it sends responses. When 192.168.6.1 pings - it receives the pings but does not reply. 

Anything (obivous) I may be overlooking here? I don't see any SD-wan rules or policy routes that would apply... Any suggestions with debug commands I can use would also be appreciated.

Thank you,