This happens when you create a blueprint struct with a class reference of a blueprint class that has Niagara component in it (not tested with c++).
The bug is persistent in UE 4.26.1
The bug only happens in packaged build, as soon as you launch the app, even before the ue4 logo. On android the app just instantly crashes. I’ll report this the proper way once I find a moment to reproduce it in a clean project.