Photoshop pdf presentation with a wrong page order

Yesterday I've been working on a pdf-presentation and its page order was predictable (repeating the order of opened project tabs in PS).

But today my PS insists on turning the actual 3rd page into the 2nd and vice versa.

While typing this question here I've "hacked" it with reordering those opened psd-file's tabs. But agree, it's not the best option! What's the reason for this issue? Could it depend on the fact that files were renamed?