NullPointerException on AbstractEntityPersister.resolveDirtyAttributeIndexes

Using build-time bytecode enhancement with lazy initialization and dirty tracking.
Using a bi-directional @OneToOne(fetch = LAZY). The problem occurs with and without @LazyToOne(NO_PROXY) on the parent.

When hibernate.bytecode.allow_enhancement_as_proxy is true:

previousState contains null values at AbstractEntityPersister.resolveDirtyAttributeIndexes, producing NPE:

When hibernate.bytecode.allow_enhancement_as_proxy is off it does not happen.

Is a reproducible example absolutely necessary in this case?

Regards