If you have your project set for inclusive blueprint nativization and are using the “Add Child Actor Component” blueprint node AND that node has a child actor class set, you will be able to package a project successfully but the resulting project will hard crash on launch with an error. Kind of like this one:
[2017.06.13-21.33.46:135][ 0]LogWindows:Error: Fatal error: [File:D:\Build\++UE4+Release-4.16+Compile\Sync\Engine\Source\Runtime\CoreUObject\Private\Serialization\AsyncLoading.cpp] [Line: 2781]
[2017.06.13-21.33.46:135][ 0]LogWindows:Error: Missing import of (/Game/NewMap): NODE_AddChildActorComponent-0_ChildActorClass_C_CAT in Package /Game/ActorClass was not found, but the package exists.
Adding a child actor component with no class set and then setting the class after with the “Set Child Actor Class” node does work. This makes me think that the issue may be related to the project not understanding that the class is in use and skipping adding it to the project. I would be happy to send someone my test project if it would help.