If the PPTX file contains a custom slideshow, which set by default and opening in Impress, this setting wasn't imported. See also commit312334f848
"tdf#47365 PPTX export: support loop attribute" and commita4b66458a7
"tdf#125071 PPTX: fix missing custom slide show export". Change-Id: I9c2b3773f6883ee795f119df5b8534fcdfa6618f Reviewed-on: https://gerrit.libreoffice.org/c/core/+/117172 Tested-by: László Németh <nemeth@numbertext.org> Reviewed-by: László Németh <nemeth@numbertext.org>