I have noticed that there are some strings in gpa that are marked as translatable, but didn't appear when running msgmerge on my Swedish po. To me it looks like these files are missing from POTFILES.in:

src/cm-unknown.c
src/cm-geldcarte.c
src/certchain.c
src/gpagenkeycardop.c
src/gpafileimportop.c
src/format-dn.c
src/keyimpeldlg.c
src/gpa-uid-list.c