Mavo expressions don't work for setting mv-mode dynamically in some cases

[karger]

According to the documentation, mv-mode should be "live" in an mv-app element; in particular it should be possible to evaluate an expr in order to set the mv-mode to edit or read. But as shown in this codepen, that doesn't work. The codepen contains three (tiny) mv-apps.

• The app that uses github storage with mv-mode="edit" as a literal works fine
• The app that uses local storage with 'mv-mode="expr"` evaluated dynamically works fine
• The app that uses github storage with 'mv-mode="edit"` evaluated dynamically does not work

This inconsistency is clearly wrong, and I'm not even sure how it is arising. It seems to me that mv-mode is a setting for the mavo interface which means that it should be managed by mavo core without any effect from choice of storage back-end/plugin. So I don't see why the github behavior is different from the local store's.