The problem seems to be org.hibernate.boot.model.internal.ClassPropertyHolder#addPropertyToMappedSuperclass which handles parameterized superclasses differently from non-parameterized superclasses. For non-parameterized superclasses, it just adds the property. For parameterized superclasses, it does some “magic”.

In this case

if ( inferredData.getTypeName().equals( getTypeName( originalValue ) ) )

seems to be the problem, because originalValue does not yet have its typeName set and thus the if-condition evaluates to false instead of adding the property and return.