When viewing the Quote record, Quote items display in a different order when viewing the record, and when viewing the record/list of Quote items in edit.
You may come across this issue when pulling a Quote document from the Print/Email button on a Quote record. Keep in mind that the Items listed in Edit mode are how the Quote Items will be listed on the document, and make adjustments to the ordering in Edit mode as needed.
Ex. Quote Item list in Edit:
Ex. Quote Items listed on Record: