Sonoma introduced a severe bug that affects all apps:
If you trigger a Save dialog one way or another, the app's icon starts bouncing in the Dock and the app isn't the frontmost process anymore. That is, it doesn't respond to keyboard until you manually bring the app back into focus by either clicking the Save dialog, app window, or the app icon in the Dock.
The same issue also happens when calling the Open dialog (in which case the icon doesn't bounce in some apps, but the app is still not responding to keyboard until you bring it back to front manually).
The bug prevents users from performing regular operations related to saving/opening documents such as specifying the file name, or cancelling the dialog etc.
The bug is still there in beta 3.