I am still experiencing this.
(Picard 2.3.2 and Classical Extras 2.0.10)
Here are two videos.
The first is a short example. At the 14 second marker I click on the left panel so to take away focus from the right panel, and you see immediately that the saving of the files speeds up considerably.
Warning: the second video is like looking wallpaper dry.
Only at the 10:44 marker I am finally able to steal the focus away from the right panel, and only then the saving speeds up.
https://www.dropbox.com/sh/6vegz0n70pbkv15/AABXAUwva6QyVt6e2HXtylJwa?dl=0