I have done this but only the first file will be added in the gdb. I have tested it with an older proces from geoprocessing history where I added 3 cad file into a gdb. running it again only 1 file is added.
Wow, I wonder if you're right about this being a new bug in 2.8. Are there any special or limiting characters in your file path, like a semi-colon, that could be stopping this operation from happening?
Could you try importing directly to the geodatabase from the catalog pane and choosing "Feature Class(es)"?
Yes, I think I have stumbled on a bug. I can import directly into the gdb but this of course will give not the desired result. Because each cad file I have to select manually and is separate imported and not all cad files are combined in the five feature classes (annotation, point, polyline, polygon, multipatch).