Calls to GetLoginItemSettings (amonst others) will get GetAppUserModelId which will implicit set a new one if there hasn't been a user defined one yet.  This causes an issue in a UWP environment where the AppUserModelId is system defined.

On the latest versions of windows the AppUserModelId defined for your notification must match exactly the one defined for your process or no notification will appear.  Got a fix in the works for this just raising here for tracking purposes.
brightray/common/application_info_win.cc
app_user_model_id_ = name;
  SetCurrentProcessExplicitAppUserModelID(app_user_model_id_.c_str());
}
PCWSTR GetRawAppUserModelID() {
  if (app_user_model_id_.empty()) {
    PWSTR current_app_id;
    if (SUCCEEDED(GetCurrentProcessExplicitAppUserModelID(&current_app_id))) {
      app_user_model_id_ = current_app_id;
    } else {
      std::string name = GetOverridenApplicationName();
      if (name.empty()) {
        name = GetApplicationName();
      }
      base::string16 generated_app_id = base::ReplaceStringPlaceholders(
        kAppUserModelIDFormat, base::UTF8ToUTF16(name), nullptr);
      SetAppUserModelID(generated_app_id);
    }
    CoTaskMemFree(current_app_id);
  }
  return app_user_model_id_.c_str();
}
bool GetAppUserModelID(ScopedHString* app_id) {
  app_id->Reset(GetRawAppUserModelID());
  return app_id->success();
}
}