Those look like the 2.79 Spaces which get converted to Workspaces when you open a 2.79 file in 2.80, but I've not seen them end up in the New Workspace menu like that before, so the question is how they got in there.

Did you open a .blend file that led to this condition, in which case can you share that .blend file? Or is this what you see with a File->New document or a fresh startup of Blender, in which case do you know if you did a File->Defaults->Save Startup FIle at some point?

Ok, I can reproduce the menu look by opening a 2.79 file and then doing File->Defaults->Save Startup File. All the existing Workspaces get added to the Add Workspace menu as shown here when you start Blender afterward:

It makes sense that it might be intended to work this way. I'm not sure how many people have actually tried this though.

What happens when you try to Add these Workspaces? Does it do nothing, or do you get an error, etc? It generally seems to work for me.

Nothing happen. Console without errors. And yes it was imported from old configuration file but still should work if this options are there or it shouldn't be imported.