Guild Wars 2

On November 6th my Guild (DT) attempted their first guild rush with 3 people. Everyone of us did it 5 times, the counter allways increased and after 15 runs the NPC was not indicated at the minimap anymore, everything seemed as if it was completed.

We then entered WvW but did not get any reward or message after the 7 minutes had passed that were left on the counter.
The guild mission screen still showed it being active with 4 hours left so I assumed we would get the rewards then but this was not the case either.

Is there any known bug with the guild rushes, or do you have to stay on the map (which would be totally stupid) or any thing how this can be avoided? We are a guild with maximum 5 people so we really have a hard time doing this missions, being cheated on the merits is not super fun for us.

That being said I assume there is no way we can be awarded the missing merits retroactively after reviewing this situation?

Indeed someone does have to present in zone at the completion of the guild rush.

If everyone leaves it appears to actually reset itself and can be done later within the 5 hour timespan.

Can this be confirmed by a developer? It is neither noted in the wiki nor on dulfy, it does not make any sense to me from a programming perspective, and it seems to be super crazy for guilds where 15 players make it in the first try as they have to wait for 28 minutes or something?

Also I opened a ticket about it and it was called a bug by the gm (and i was told to post here)