Import Linetypes - Not working

Trying to import linetypes from another file. After choosing the file and choosing which linetypes to import, the dialog closes and nothing changed. No new linetypes visible. No new linetypes selectable from other dialogs either.

Strangely, I used scriptcontext to get the activeDoc linetypes and it said they were there…

This is still an issue in both R6 and R7WIP