Multiple VLANs configured on non-fortilink interface.

Hi Everyone, This is my first post (and my first Fortigate).  

I'm just starting to play around with a Fortigate 100F and I can see in the security rating section under security fabric this message:

"Non-FortiLink interfaces should not have multiple VLANs configured on them."

I assume that because this is my only Fortinet device that this warning doesn't really mean anything. I have not been able to find anything relating to this message out on the internet or in the forum.  Are there any issues that I should know about running multiple VLANs on a non-fortilink interface?

Thanks in advance,

John