I did not reproduce the problem. Using MLT XML as a nested clip only works properly when the video mode of each matches. Do yours?
Is it necessary to include Elastic Scale to reproduce it?
It is even necessary to nest a project as clip to reproduce it? Please export intro.mlt by itself and see if the result looks OK. Rich Text has a bug on systems with Windows display scale that is not 100%. What is yours (Windows Settings > System > Display > Scale and layout)? This is improved on the next version 20.10 already in beta.