The following has happened on my PC twice so far, but I haven’t found a way to reliably reproduce it…
After launching Designer, if I try to expand a database which was already present in the Applications panel, it sometimes crashes Notes.
At the moment of the crash, the text “Loading…” appears where the database title should be, and the icon next to the title is stuck on the generic database cylinder (i.e. the icon for the specific database has not appeared).