I described the problem here: https://discourse.hibernate.org/t/problem-with-generate-id-in-hibernate-6/7369
I looked a little, the error occurs when hibernate tries to process a property in an entity by type:

@ManyToOne
@JoinColumns({
        @JoinColumn(name = "channelId", referencedColumnName = "channel_id"),
        @JoinColumn(name = "messageId", referencedColumnName = "id")
})
private ChannelMessage message;

And inside ChannelMessage these fields:

@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE)
private long id;

and

@Generated(GenerationTime.INSERT)
private long channelId;

And when hibernate processes these fields, generatorCreator field is filled only for{{channelId}}. Because in PropertyBinder class in generatorCreator method it looks for the ValueGenerationType.class annotation (or child).

But maybe I didn't fully understand how it should actually work
I have attached test cases (may need to run a couple of times).