Thank you!!
This hack work for me in 4.18.3.
None of the others solutions in this thread let me package the game but this hack made the trick!
Not only that!!
Now the values in blueprint child actor variables don’t reset at editor startup!
Your comment should be marked as “the solution”.
Ok, after all a have find out the way to workaround this problem. I add ChildActor Component and specify the ChildActor, set proper transform to component, then clear the ChildActor and set it in Construction script with all details. It’s better than nothing.
My current working theory is that this error can occur if there’s a cyclic dependency in your project making the compile order unclear or unresolvable. If, for example, Class A casts a child component to Class B and sets a variable on it, while meanwhile Class B does some operation on an instance of Class A, you’re going to run into problems because Class A can’t be compiled until Class B has been compiled, but Class B can’t be compiled until Class A is compiled.
My experience has been that these sorts of circular references can behave in strange ways, since what they do depends entirely on the order in which assets actually get compiled, which is why creating child objects of an offending class could conceivably correct the issue, since then the parent object could simply as a matter of luck be compiled in time to be used.
This is just a theory, but I recently resolved one of these issues by cleaning up my inheritance architecture so two objects no longer needed to know about each other to compile. Or I just got lucky.
Epic’s own code concedes that there isn’t a clear handle yet on what’s causing this.
if (ChildActorClass == nullptr)
{
// It is unknown how this state can come to be, so for now we'll simply correct the issue and record that it occurs and
// and if it is occurring frequently, then investigate how the state comes to pass
if (!ensureAlwaysMsgf(ChildActorTemplate == nullptr, TEXT("Found unexpected ChildActorTemplate %s when ChildActorClass is null"), *ChildActorTemplate->GetFullName()))
{
ChildActorTemplate = nullptr;
}
}In my case, I was doing some changes to variables on begin play for the child actors that I had in my blueprint. I tried the solutions here but didn’t have any luck. I tried moving this over to the construction script to set the values I needed and it seemed to resolve the issue. I’m not sure if this will help anyone else but it worked for me.