Fabric : Unidentified in Lakehouse

I've an interesting thing in Microsoft Fabric, a Unidentified folder :

According to Microsoft : 

"The Unidentified Area is a part of the managed area of your lake which displays any folders or files in the managed area with no associated tables in SyMS. For example, if a user were to drop an unsupported folder/file in the managed area, eg: a directory full of pictures or audio, this would not get picked up by our auto-detection process and hence not have an associated table. In this case, this folder would be found in this unidentified area. The main purpose of this new section is to promote either deleting these files from the managed area or moving them to the file section for further processing."

Strangly,  I was just creating tables in Lakehouse with some PySpark scripts and somehow the table was organized into a Unidentified folder. But, when I watched it a  couple of seconds later, it was gone. 

Theo Lachev also write a blogpost about the unidentified folder :

"Going quickly through the list, the managed area (Tables) can’t be organized in subfolders. If you try to paint outside the “canvas”, the delta tables will end up in an Unidentified folder and they won’t be automatically registered. Hopefully, this is a preview limitation since I don’t see you can implement a medallion file organization if that’s your thing."

It still not quite clear to me what the "Unidentified" folder means. In my example it seems a temporary issue because it disappeared after a few moments. If someone has more information about this, I'm curious. Let me know.