I have found the following:
1) If you create a new document and you add by error two linefeeds, delete one of them, save and re-edit … then line feeds are gone completely
2) Old descriptions, created before latest patch, do not show line feeds on re-editing.
3) maybe another topic:
On creating a new document sometimes most of the fields on the form (description, flags etc.) have the values of the latest document you opened for re-editing, if you cancelled the previous re-editing (no update document)