`GetLastValidationError()` returns empty list for failed `SubmitNewModFileForMod()` call with `ErrorConditionTypes::InvalidArgsError`

[lethal-guitar]

I encountered an issue where a certain mod file failed to upload, with SubmitNewModFileForMod() reporting an ErrorConditionTypes::InvalidArgsError. However, GetLastValidationError() returned an empty list, so I was not able to see the details of the problem.
Based on the SDK debug output I was able to determine that the same file can't be uploaded to multiple mods:

[10:46:10.3088638:308ms][Error][Http] Non 200-204 response received: {"error":{"code":422,"error_ref":13009,"message":"This file has already been uploaded to \"Untitled\". A file cannot be uploaded to multiple Levels."}}

It would be great to be able to determine this in code however, so that I can show corresponding feedback to the user.

My code looks basically like this:

  void uploadFileForMod()
  {
    Modio::CreateModFileParams params;
    params.RootDirectory = (mTempDirPath / "map").u8string();

    Modio::SubmitNewModFileForMod(mNewModId, params);
  }

  void onModManagementEvent(const Modio::ModManagementEvent& ev)
  {
    if (ev.Event == Modio::ModManagementEvent::EventType::Uploaded)
    {
      if (!ev.Status)
      {
        mState = State::UploadedSuccessfully;
      }
      else
      {
        mState = State::UploadError;
      
        if (ec == Modio::ErrorConditionTypes::InvalidArgsError)
        {
          LOG_F(ERROR, "SubmitNewModFileForMod() failed:");
      
          const auto errors = Modio::GetLastValidationError();   // <---------------------- returns empty list
          for (const auto& error : errors)
          {
            LOG_F(ERROR, "'%s': %s", error.Field.c_str(), error.Error.c_str());
          }
        }
        else
        {
          LOG_F(ERROR, "SubmitNewModFileForMod() failed: %s", ec.message().c_str());
        }
      }
    }
  }

Perhaps this is a user error on my part, but I didn't find anything in the documentation indicating that validation errors for SubmitNewModFileForMod need different handling than the usual approach.