If a blueprint has its root component set in code, adding that blueprint as the child actor component of a second blueprint will cause the first to become dirty anytime the second is opened or edited. This does not occur if the root component is not defined in code.
Yes - first blueprint does not become dirty in 4.14 Binary (CL 3249277)
MyActorBP becomes dirty
Editing one blueprint does not dirty another that is not a child.
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