certain letters do not work in openoffice (sometimes)

This bug is so weird and strange that I hardly know how to formulate it.

When I open certain documents that I have, some (non-English) letters cannot be used. Namely, the Swedish letters å ö ä. Writing them results in some weird characters (see the attached screenshot). Other characters turn out wrong as well, such as "»", "é", or sometimes É.

On the other hand, this does not always happen. Sometimes, if I start openoffice from the application menu instead of starting it by opening a document, the letters work fine. Sometimes the capital Ö Ä Å fail whereas the small letters work, and so on.

>locale

gives

LANG=en_US.UTF-8
LC_CTYPE=sv_SE.utf8
LC_NUMERIC=sv_SE.utf8
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY=sv_SE.utf8
LC_MESSAGES="en_US.UTF-8"
LC_PAPER=sv_SE.utf8
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=

But I've tried varying that...