Thank you for your bug report, that's because synaptic has been changed to use launchpad translations, which means the translations have been removed from the binary in favor of langpacks, they should be included again in the next langpack update
Thank you for your bug report, that's because synaptic has been changed to use launchpad translations, which means the translations have been removed from the binary in favor of langpacks, they should be included again in the next langpack update