This is the Spirit Talk Quest, where Shannon is supposed to summon some spirits after the fight in the dock warehouse.

This is what happened:
1. Fight ends
2. Shannon leaves team
3. Shannon runs to souther room, standing there (this is where walkthroughs, etc. report she should summon some spirits.) until my own character moves again.
4. Shannon runs to a position near the warehouse entrance.
5. Shannon doesnt do anything at all.

At this point, she will not leave the vicinity of the warehouse entrance. When my character moves around in that area, she will follow. Otherwise she'll just stand there and do nothing.

I even tried to load, I tried to replay the whole level. Nothing. Nicely reproducible. And an early end for this game. Pretty sad.

(this is with SR version 1.2.0)

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Update: Got around this somehow. Replaying the level several times finally fixed it. Now my Team wont join me in the Universal Brotherhood level, even though I opened the door for them. Again, replaying... replaying....
great stuff. This game seems to be in a rather poor state, regarding scripting. And that after several patches and a major expansion.

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Update:
And another funny gamestopper in the "The hunt begins" mission. Cant progress, because a hallway opened up by a Bugspirit is not accessible to my team. Great scripting right there.