JabRef 3.8.2
windows 10 10.0 amd64
Java 1.8.0_121

I think this is not actually a bug (although I'm not sure), but I just wanted to report it as a reference in case someone comes across this problem.

Steps to reproduce:

1. Add the following entry to your JabRef database:

@Article{Redding2006,
  author   = {Redding, David W. and Mooers, Arne {\O}.},
  title    = {{Incorporating {evolutionary} {measures} into {conservation} {prioritization}}},
  journal  = {Conservation Biology},
  year     = {2006},
  volume   = {20},
  pages    = {1670--1678},
}

2. Check the entry in the entry preview. It is correctly displayed as:

Redding, D. W. & Mooers, A. Ø. Incorporating evolutionary measures into conservation prioritization Conservation Biology, 2006, 20, 1670-1678

3. Now change the special character of the second author's name. Change {\O}. to {\{O}}.. You end up with the following entry:

@Article{Redding2006,
  author   = {Redding, David W. and Mooers, Arne {\{O}}.},
  title    = {{Incorporating {evolutionary} {measures} into {conservation} {prioritization}}},
  journal  = {Conservation Biology},
  year     = {2006},
  volume   = {20},
  pages    = {1670--1678},
}

4. Save the database and close JabRef.
5. Restart JabRef and reopen the database. The entry preview of the article is no longer correctly displayed. Instead, the following is shown:

Redding, D. W. & Mooers, A. Ø#.#.

Indeed, the BibTex source panel also shows just:

@Article{Redding2006,
author   = {Redding, David W. and Mooers, Arne {\{O}}.}

6. Close JabRef and open the bibtex file with a text editor of your choice. Search for Redding2006. As you can see, the article entry is still complete. Change the author's name back to {\O}. The entry should look again like this:

@Article{Redding2006,
  author   = {Redding, David W. and Mooers, Arne {\O}.},
  title    = {{Incorporating {evolutionary} {measures} into {conservation} {prioritization}}},
  journal  = {Conservation Biology},
  year     = {2006},
  volume   = {20},
  pages    = {1670--1678},
}

7. Restart JabRef and open the database. The entry is again correctly displayed.

It appears that using {\{O}} instead of {\O} causes issues with the entry preview of JabRef. As far as I can tell {\O} is the proper way of writing the respective character in Latex/BibTex (http://www.bibtex.org/SpecialSymbols/), but sometimes it is suggested to use the additional set of braces. While this works for many special characters, it does not in this case. I just wanted to point out this behaviour, but, as mentioned at the beginning, I don't think this is a bug with JabRef. In fact, JabRef is probably working as intended, as this wrong (?) special character is a user mistake.