I think I found a bug. When I type a parenthesis or a bracket in Formula libreoffice crashes. I receive a message:
Warning: Connect() failed: No such file or directory.
I used the 3.4.0rc2 debs provided by the download section in the official site.
Can't be sure, because there's no backtrace here for example, but this might be the same as bug #37668
*** This bug has been marked as a duplicate of bug 37668 ***