Apparently https://gerrit.wikimedia.org/r/#/c/342083/ made the edit summary sticky not just while switching but also between separate edit sessions.
Steps to reproduce:
- Open VE
- Edit something
- On the save page dialog provide a summary
- Switch to NWE
- Switch back to VE
- Save the page.
- Now open VE again.
- Edit something
- Open Save dialog
Observe that the Edit Summary of previous session is still there although its a new edit session.
Another bad side effect of this is, during step 7 if you open VE through a section edit link, Edit Summary is now not showing the name of that section anymore.