Same "error" is showing when you add delta using shortcut, until some scan will identify delta as table. for us it took ~30s,
I agree that MS could better handle messages , not show all as unidentified without detailed info.
Thanks Piotr Pałka. I will add a note in the blog, while the Delta tables are being created, it may temporarily create the files which will show up as Unidentified and will go away after the creation process.