EDITED as I have concluded this is now more a Chromebook than a LO issue. I did manage to copy and paste as rtf but with a fresh download of LO it remained. I will add back if I find and learn anything on a Chromebook form that is relevant here.
Edited to say I have now attached two attachments made in LibreOffice and showing what happens. It gives a partial answer as I discovered pasting as RTF works.
It still begs the question of why all the other ways you can copy and paste have the strange symbols.
If I create a new ODT file and try to paste into that the same thing happens. In addition, if I simply copy and paste I get the problem and every sentence is numbered. When I try to paste special, then I lose the numbers and get the symbols.
This happens when I upload a file. Please, can someone tell me why and what to do?
It also happens when I try to copy and paste into a downloaded template to another.
I am using a Chromebook.
I uploaded to Prowritingaid.com (Cannot use the editor in libreoffice so have to use the web version.)
Due to Chromebook limitations I can only get libreoffice 5.2
In answer to comments about ISO’s below:
The problem happens even copying from one Libreoffice file to another. The document where I first found the problem is a libreoffice ODT file. I uploaded using the Chrome browser. The document was formatted, but the problem is in the body text, not the headers. I understand what you say about the apostrophe but why would it happen in libreoffice files when I am not uploading to anywhere, but copying and pasting?
If the problem happens in ODT files, then is there something that I can do to change things in my version of libreoffice. Reinstalling has not solved the problem. Chromebooks can only get to Libroffice 5.2.
(I do not know how to put a BOM mark before a document. I am lost there. For people like me, we need not just the information you give, but also the information as to how you would actually do it from the point of opening the file! I will ask another question about that!)
(edit: fixed download-file links)