My friends and I just spent ~1:30:00 running onslaught on expert. And right when we went to rally before the final boss, it error coded us all. I believe this has been an issue before, so I'm just letting you know that it's happening again. It's such a terrible feeling to be pulled out after spending that much time. We were on Widow's Court (Expert) Solar warlock, Prismatic Warlock, and a Stasis Titan.