At the beginning of this let me preface that I am a networking noob. The last time that I setup a router was 6-7 years ago with my still working USR8200 which has required no fiddling ...

I did do some debugging on the Fortigate and the 8212. I setup a running ping from my laptop on another VLAN (150 in this case) to ping the address on the 105 VLAN.