I got Slings and Arrows book 6 on Kindle recently and had a terrible formating issue with italic. There was no space between previous word and italicised word.
I bought Slings and Arrows
back before ePub and KF8. I bought it in MS Reader format. I do not recall having an issue with italics. But then, maybe it was remade for KF8 using PDF as the source. I have seen some eBooks made from a PDF source have that very issue with italics.
As for downloading updated Trek books, I would not do it. All the errors I noticed while reading have been fixed. Without reading again, no way to be sure that S&S fixed all the noticeable errors.