Analysable-level files are like tmp files we later merge to train the model or to get predictions. They can be stored both at unlabelled or labelled file areas but I introduced a regression in MDL-59661 when rebasing over a related issue that introduced changes in the same part of the code. The thing is as simple as changing $target for $includetarget ($target) does not exist in that method's scope.

If this would be a bug in stables I would advocate to update the files properly and switch them to the proper filearea but being only master and not even alpha release I would vote for just dump all analysable files. I've tried to do it properly and move files to the proper filearea using copy_file_from_storedfile but I fail to retrieve the files later.