When clicking “show forms” and filling in, everything looks fine. However, clicking “Show forms” again after filling in text, æ and å just disappears while ø is changed to ł. If filling in ł it disappears. There are problems with other special characters as well.
Using other readers, like Firefox, works as expected.
Thankful for input and ideas.
I filed a bug at 471796 – pdf with forms does not handle special characters