Languages on Multisite and Subsites – Auto Translations (Partially) not Loading

Hello everyone,

after the update of Jetpack to 3.8.0, I found that translations were missing. I was told that Jetpack had beed added to the translate project – and my locale (de_DE) was no longer shipped with the plugin files, since 100% completed.

However, we could not find out why translations were not loaded automatically. So, I installed them manually and closed the case for the time being. But it seems I cannot ignore this any longer.

Now I have another plugin, bbpress, which I would love to see translated automatically. But again, the translations do not load. And it seems I am far alone with this problem, since no search in the support forums turns up anyting on this.

WordPress itself is translated, however, and when updating, I am sometimes notified of available translations. But no plugin translations are loaded automatically (I assume they would be put into wp-content/languages/plugins? Or are they loaded directly from wordpress.org, never even showing up in my FTP files?).

Could this have anything to do with me running a MS installation? Interestingly, the network language remains English (US), even if I switch it to German in the Network settings. And of the subsites some are in English, some in German. At least they are translated alright. However, with increasing numbers of translations removed from plugins, my problem will certainly not go away.

Thanks for your efforts!
Manuel