The flow.xml validation reports unrecognised flow identifier and marks the line with an error annotation. However, the flow redirects to the subflow correctly.
flow-location-pattern is "/**/flow.xml"
<subflow-state id="userHome" subflow="home">
I noticed that the type-ahead should suggest the list of available flow identifiers. This doesn't work as well, it's suggesting 'flow' as the only known identifier.