IMAP FetchHeaders and FetchBundle resuls in emails in different order

I have been using Chilkat IMAP component to read e-mails but lately I made a chance to the software. Before I used

bundle=imap.FetchBundle(messageSet);

And I replaced it with

bundle = imap.FetchHeaders(messageSet);

But the problem is that now headers are in different order. I added

bundle.SortByDate(true);

Now most of headers are in same order than in Lotus Notes but a few are in different order.

I think this is mostly Domino problem, FetchHeaders returns messages where IMAP UID:s aren't always in sequence. I solved this problem by sorting headers vy UID.