Some translations are missing in Kleopatra in spite of 100% translation in German, French and Japanese (those were the ones I checked, the others are surely the same as the latter two).

In German I am missing:
"<b>Decryption not possible: %1</b><br />The data was not encrypted for any secret key in your certificate list."
from src/crypto/decryptverifytask.cpp:272. The other strings there which were changed at the same time should be affected, too. See T7295.
I find only a part of that string in the trunk6 translations.

For JA and FR I only did a quick check for key creation.
Noticed as not translated from the key creation dialog:
"Advanced options", "Key Material", "Valid until (between %1 and %2):"

We should have the same kf5 .po files for at least those languages, too.