Artem K.,
I checked and @NotFound works, even without this fix, when a OneToOne association references an not existing entity instance.

Not sure what you mean by " it just does not address the underlying issue of this bug", this issue is related with the fact persisting a null @OneToOne not optional association annotated with @NotFound throw an exception. In my opinion this is the correct behaviour. As I wrote @NotFound should throw an exception when a @OneToOne association is not marked as optional and the association is null.
In order to obtain the behaviour introduced by this fix @NoFound should be used in conjunction with optional = true.