pages selected

I tried to change the margins of a PDF ( https://deftpdf.com/resize-pdf ), but the page selection didn't work well. I will exemplify what happened, in a PDF with 3 pages, if I select only pages 1 and 3 to be changed, wanting page 2 to remain unchanged, when downloading the file it edited pages 1 and 2. For a PDF of 4 pages, if I select page 1 and page 4, it edits page 1 and 2. Anyway, practically it is editing the number of pages selected no matter the page number, it just applies the edit to the first pages accordingly with the selected quantity.