Updating translations doesn't work

Updating translations via Edit/Preferences/Updates Translations or Help/Resource Manager/Languages seems to work, but, even after a MuseScore restart, doesn't result in the translations being updated, even though the corresponding .qm files are where they should be.

Esp. annoying as it prevents translators from testing their work.

Could it be that MuseScore 3 still loads them from the 2.x repository?
Edit: apparently not:
static inline QString baseAddr() { return "http://extensions.musescore.org/3.0/"; }
and

void ResourceManager::displayLanguages()
      {
      // Download details.json
      DownloadUtils js(this);
      js.setTarget(baseAddr() + "languages/details.json");
      js.download();

So something in the upload from transifex seems to go wrong? Something in https://github.com/musescore/tx2s3 although c3c5cc4 looks correct?