Sometimes it's better to write less words, but be punctual and get straight to the point, and better write in your native language than using translator.

I don't know why would you use Metamask and all your extensions in the same time with Chipmixer, but Metamask is not malware that can steal your Bitcoins, unless you downloaded some infected version.
Maybe you need to clean and scan your whole computer for malware, or even better make fresh system reinstall.

What do you mean bug disappeared?

So bug appears and disappears at unknown times and only when you are not looking.

It's not that I don't trust you, but it looks like you took some funny mushrooms.