Hard to get good data on it. We have a few instances of the crash, but I’ve only managed to trap it in a debugger once.
I’m looking through the most recent 10 instances we have of a crash in FStructuredArchiveSlot, and only half of them involve Niagara, so that is likely a red herring. The bug is not consistent, in that someone can hit the crash, but successfully load in their next session. One’s especially odd is one team member was hitting it fairly frequently while performing a super common action (starting PIE). A couple others have hit it, but less frequently. If it’s a data race/threading issue, then that wouldn’t be surprising.
Do all of the instances you see involve FAsyncLoadingThread2? I believe FAsyncLoadingThread2 was made default as of 5.5.1, so perhaps it’s a race or bug in async loading?