This issue persists despite the alleged fix in the scheduled maintenance on July 26th.
I held back on posting more info earlier because this was supposed to be fixed, but here it is now:
Players who are added to the party play queue after the queue has already been established are more likely to encounter the bug
If you are affected on the first run of the day, the rest of your runs that day will likely be affected
If you are not affected on the first run of the day, you probably won't encounter the bug in the rest of your runs for that day
Changing queue hosts, party configurations, or queuing methods will not unbug you
Restarting your game client or your PC will not unbug you
The bug affects all characters on your account for the day
Your bugged status seems to go away upon daily reset
Knowing these points, my group has a pretty reliable workaround in the meantime. We've currently tested this method once, and everyone in our 9-man group was able to receive rewards that day. Can anyone else test this method so we have more information to draw from?
The host adds everyone to their party before establishing the queue
If there are more than 6 players participating in the expedition, split the group into separate expeditions so that everyone is in a host party before the queue is up.
The important point is that no one has to be manually invited into the party play queue.
The host(s) establish their queue via party play, enter the raid, complete the raid
After finishing the first run, the separated groups can be merged back into one expedition as normal for the second and third runs
