I was working on my PC, and all of a sudden, a window popped up saying that one of my sound devices has been unplugged, do I want KDE to let it remain this way? I chose to fiddle around a bit and see whether KDE was right. I tested all the speakers and sound devices… Everything fine. Why did KDE show that message? Is it a bug?
When you figure it out, please let me know also. 
Glad to read there was no effect on your audio.
Good luck!