Worth noting that the exception is not throws during standard execution, but only in the context of a Maven plugin execution. The exception is indeed related to a missing namespace, i.e. it's triggered by XsiTypeLoader::parseXsiType returning a null JaxBeanInfo when idx == -1 in

int idx = atts.getIndex(WellKnownNamespace.XML_SCHEMA_INSTANCE,"type");

while parsing the Envers generated mappings.

Why this only throws in the context of a Maven plugin execution and not during app runtime, it is obscure to me.