Strangely enough, this goof describes the downfall of the series perfectly.

Season 1: 10 Stars, simply amazing, beyond expectations.

Season 2: 8 Stars. Very good with many lovely story telling.

Season 3: ... What the hell was that?

In one of the latest episodes of season 3, Yennefer says "Look at all these Gold, left here to rust".

Yennefer is a powerful sorcerer, that has lived for centuries and has extensive knowledge in alchemy. She would most definitely know that Gold does not rust. That's what makes it so special.

And that summarize the quality of the 3rd season and how once an amazing show with beautiful story, wide characters and extended knowledge has now become a total waste of time.