I don't have a ready-made solution I'm afraid but subsequent to my earlier post quoted by you, I found that the problem seemed to be the way Generations uses the GEDCOM tag CONC.
If you want to throw a new line in a note then the tag should be CONT. Generations' use of CONC in such circumstances is why your sentences after the export are running together.
On the stripping out of the initial characters of lines, I didn't experience this with letters, only with numerics. What seemed to be happening with me is that in some cases (but by no means all) 1841 as the initial "word" in a note was GEDCOMed as, for example,
rather than simply as 0@N33@ NOTE 1841 Eastington, Gloucestershire
the latter being correct GEDCOM usage as I understand it. Obviously, with a lot of notes it is very tedious to edit the GEDCOM file before importing elsewhere and equally tedious to edit post-import. I've started using another program which seems to use CONC and CONT correctly so that having reformatted my notes I find that subsequent exports using the new program work ok.
Sorry not to be able to offer a quick fix but hope this helps in understanding why the problem is occurring.