The project size: 4 flows, 60 players, 120 staves, 3500 bars of music.
Memory usage, with “Silent” playback template, is about 25 Gb running on Windows 10 pro. The .dorico project file size is about 40 Mb.
When I quit Dorico, the main window disappears immediately, but there is then several minutes wait before the Hub window appears. In that time, something is apparently running on a single CPU thread, and the memory usage slowly ramps down from 25 Gb to around 4 Gb.
Presumably something is “carefully” freeing memory piece by piece in the reverse order to how it was allocated, rather than freeing all of it in one operation.