While reading(Through RepositoryItemReader) and writing in same table some items are skipped by reader in spring batch?

Question

I have a spring batch application that reads and writes into the same table. I have used pagination for reading the items from the table as my data volume is quite high. When I set the chunk size as more than 1 then my pagination number is getting updated wrongly and hence failing to read some items from the table. Any idea?

@Bean
    @StepScope
    public RepositoryItemReader<DedWorkFlowResponse> dedWorkFlowResponseItemReader() {

        return new RepositoryItemReaderBuilder<DedWorkFlowResponse>()
                .name("dedWorkFlowResponseItemReader")
                .methodName("findByPickedIs")
                .arguments(Collections.singletonList(false))
                .pageSize(100)
                .repository(dedWorkFlowResponseRepository)
                .sorts(Collections.singletonMap("id", Sort.Direction.ASC))
                .build();
    }


public interface DedWorkFlowResponseRepository extends JpaRepository<DedWorkFlowResponse, Long> {
    public Page<DedWorkFlowResponse> findByPickedIs(boolean picked,Pageable pageable);
}


@Component
public class Writer implements ItemWriter<DedWorkFlowResponse> {

    @Autowired
    ResponseRepository responseRepository;

    @Autowired
    DedWorkFlowResponseRepository dedWorkFlowResponseRepository;


    @Override
    public void write(List<? extends DedWorkFlowResponse> list) throws Exception {
        List<Response> responses = new ArrayList<>();

        list.stream().forEach(dedWorkFlowResponse ->{

            Response response = new Response();
            response.setName(dedWorkFlowResponse.getName());
            response.setProcessedDate(new Date(System.currentTimeMillis()));

            System.out.println(response.toString());
            responses.add(response);

            dedWorkFlowResponse.setPicked(true);
            dedWorkFlowResponseRepository.saveAndFlush(dedWorkFlowResponse);
        } );

        responseRepository.saveAll(responses);
    }
}

In writer I am updating some value in DedWorkFlowResponse Table