This happened last night, but I didn't really put it together until today. After I ran AK last night, when I came back into the normal world I was no longer in my FC. Only a few of us were on and no one could remove me, so I know this wasn't the case. At first I thought my account was hacked this morning, but that didn't seem to be the case either.

It looks like I was just auto-kicked from my FC last night after leaving the instance server Amdapor Keep. First time this has happened, so I can't name any other instance. Just thought it was odd.