An external transition on a state inside a <parallel> targets its own descendants, so the whole parallel state is exited and re-entered.
No initial state, transition or history default can ever lead to the state.
A done.state.X / done.invoke.X transition waits for something that can never happen.
An earlier transition in the same state, without a condition, handles every event this one does.
The kinds of authoring warning
compile()reports onmodel.warnings.