This seems to be a bug in the Mac version: Export Section Slice… as DWG, options: Projection = true section (orthographic)
Result should be the 2D section projected correctly to the section plane I believe. On the PC version I found that to be he case in the old version I had still on a PC.
I don’t think you should have to orientate the viewport into the desired projection with this option, although I can do that as a workaround and choose screen projection instead having an orthographic camera and perfectly aligned view.
The option for sure projection should make that unnecessary