Not a huge thing...but kind of annoying. I wasn't aware that once you summon your companion it just cancels out the duty finder, with no warning (at least I didn't see one). So, I was finishing up my hunting log thinking I was still in queue for an hour or so before I realized what happened. I tried again and sure enough, it just throws you out of the duty finder with no warning at all. I sure hope they fix this soon. They at least need to warn people when it happens. You should be able to queue, summon companion, and when queue is ready it would warn you to dismiss your companion or you can't participate.
UPDATE: Well, I just noticed that there is indeed a chat message that comes up in red when you summon your companion while in the duty finder. I didn't see it before, but its there. They still need to make it a little more obvious though, it's really subtle with all the Gil spammers right now. (my blacklist is darn near full, not even bothering anymore)