I encountered a bug when dealing with hard reference (TSubclassOf) and BP class. Hard reference to BP class may cause BP compile error. See below:

Steps to Reproduce

• Create a new plugin with a module (runtime; LoadingPhase: Default). Define a simple UStruct, FMyDummyStruct, in this module.

"Modules": [
{
	"Name": "DummyPlugin",
	"Type": "Runtime",
	"LoadingPhase": "Default"
}
]

USTRUCT(BlueprintType)
struct FMyDummyStruct
{
	GENERATED_BODY()
};

• Create a BP FlowNode, FN_Test, in the project Content folder. In FN_Test, declare a variable with type FMyDummyStruct. So far, everything works just fine.

• In Project Settings, reference FN_Test in OverridenNodeCategories

Since OverridenNodeCategories is a hard reference to the BP FlowNode (TMap<TSubclassOf<class UFlowNode>, FString>), when I restart the project, the following errors occurs:

To fix this error, I changed hard reference (TSubclassOf) in FlowGraphSettings to TSoftClassPtr.

Let me know if I was wrong.