The mistake and the bait [Puzzle]

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KlekleLegacy
A simple puzzle from one of my recent games.
 
Here is the following position:
I was up by three pawns and I had the advantage. My opponent had just played 30.wqc3-h3+, forking my king and my knight. I answered with 30...bkc8-d8, and then White, eager to gain back material, captured my knight. How is that a mistake? Identify the move I played which justifies why it was a mistake.
 
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Bonus:
In this position from the same game, I failed to present a good followup for my attack according to the engine. Which continuation I missed would have been the best (find the only one that would give me a slight advantage over my opponent)?