Our guild, The Amazon Basin [AB] on SBI has been running Guild Missions since they were released.
We’re really enjoying them, so thanks for the addition of some great Guild-oriented content that gets us playing together and earns us both Guild and Personal rewards…Kudos!
We have noticed a few ‘oddities’ here and there that I thought I’d compile. I did browse for a bit through the forums and didn’t see them mentioned, but if there are duplicate threads about these, my apologies. I’m putting these down as ‘bugs’ because they don’t behave the way I expect, but it’s possible they are meant to work this way and it’s my understanding of Guild Missions that is ‘buggy’. 
The first bug we have seen is that any of our members who are NOT based on SBI cannot see the Guild Mission information. They are able to guest to SBI and participate and earn credit, but the information doesn’t show up for them as to who our bounty targets are, which trek locations we are after, or what Rush or Challenge Missions we have active. Their “Active Mission” window in the Guild Interface remains completely blank. My impression is that, since they are able to earn the personal rewards as a member of the guild for participating (i.e. the 50s, the 2 rare or better items, and the Guild Commendations), Guild Missions are indeed intended to benefit all members of the Guild regardless of what server their account is based on. So it seems odd that they won’t see the information.
Second, those who are based on servers other than SBI but guesting over to participate in Guild Missions with the guild cannot participate at all in Guild Trek. Even if we tell them a location, when they arrive at the location, the glowing circle isn’t visible to them to interact with.
The third and final issue we’ve seen is related to the permissions for Guild Missions, called ‘Mission Control’ in the Ranks tab under Permissions. Only our Leadership Team has this ability checked. We’ve tested it, and from the point of view of ‘activating’ Guild Missions (i.e. clicking on the “Activate” button for a particular mission from the Current Upgrades / Consumables list) it works properly.
However, the second part, “Interact with items in the world to kick off Guild Challenges” doesn’t seem to be working properly. Members of our Guild who do NOT have the ‘Mission Control’ permission are able to “Interact” with the banners for Guild Rush and Guild Challenge and begin the event, sometimes very prematurely. For example, we will plan to run Guild Rush at 5 PM server time. I may “Activate” the Rush at 3 pm to give folks time to make their way to the location if they haven’t mapped it yet. By the definition of the permissions, no one should be able to start the Rush until a member of the rank with “Mission Control” permission touches it. However, that’s not the case, so we’ve had to stop “activating” it in advance as a result.
Thanks for checking into this, whenever you get the chance. They aren’t MAJOR issues, since we’ve been able to work around them, but better you know and be advised.