Specification.where().and()在query by specification spring中的意外行为？

public class CustomSpecification implements Specification<Entity> {
    private Specification<Entity> previousSpecification;
    private Predicate additionalPredicate;

    public CustomSpecification(Specification<Entity> previousSpecification, Predicate additionalPredicate) {
        this.previousSpecification = previousSpecification;
        this.additionalPredicate = additionalPredicate;
    }

    @Override
    public Predicate toPredicate(Root<Entity> root, CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) {
        Predicate combinedPredicate = previousSpecification.toPredicate(root, query, criteriaBuilder);
        if (additionalPredicate != null) {
            combinedPredicate = criteriaBuilder.and(combinedPredicate, additionalPredicate);
        }
        return combinedPredicate;
    }
}

Specification<Entity> specification = Specification.where(null);

// 第一个条件
Predicate condition1 = criteriaBuilder.equal(root.get("field1"), value1);
specification = new CustomSpecification(specification, condition1);

// 第二个条件
Predicate condition2 = criteriaBuilder.like(root.get("field2"), "%" + value2 + "%");
specification = new CustomSpecification(specification, condition2);

// 执行查询
List<Entity> result = repository.findAll(specification);