Hi.
When using the DHCPv6 relay, I can see that the MikroTik is adding an option 18. but I am not sure what the value relates to:
000000e = 14 as a decimal. Interface 14? I dont have an interface 14.
No option 37 is added - which should be remote circuit ID, similar to DHCPv4 Option 82 - Can we get it please 
With the VLAN information