I didn’t see a reference to this anywhere. After opening a document and choosing "Save As…), one would expect all selectable folders to appear selectable (by not appearing greyed out in the dialog). The expected folders are indeed selectable, but they only become un-greyed at the level of selection, and not deeper. So, if I am saving into a nested folder, the first folder I select un-greys other folders at that same level, but not folders at the next deeper level that are selectable. I hope that makes sense. It’s only the appearance, and not the function, that is off.
What View Style are you using?
In Column View, I see a very slight delay of about 0.2 seconds before each hierarch of folders is ‘ungreyed’, and once shown full, returning to that folder shows the contents instantly.
Dorico doesn’t create the Save dialog itself: it asks the OS to make one. There are different methods you can use to ask the OS, but this is likely to be an OS issue.
I see what you’re describing today, where there is just a slight delay and then the folders appear as expected. I’ll work for a while and see if it changes as the application is open for longer. Last night I had had Dorico open for several hours.