Knot in the Yarn

Hi, I found a knot in this yarn. It’s pretty expensive yarn (>5 euros per 50g, Merino) and I find this pretty annoying. Question: Is this normal, or is it grounds for a complaint? And how should I handle it? Cut it out? But then I’d have to weave in ends, right?

It’s unsightly, but normal. Even expensive yarn can have knots.
You can’t really complain about that. You’re left with only two options: Either cut it off and weave in the ends, or work it into your project. It might be a Frankfurt knot—in that case, you can trim the ends pretty close to the knot.

I had this happen recently with some sock yarn. Several knots, and then a plastic strip was knotted right in there too… so I filed a complaint. I got a gift certificate for it, but I thought it was justified. I wouldn’t say anything about just 1 or 2 knots, though—that kind of thing just happens sometimes.

1–2 knots are normal; that just happens in machine production. But if there are more than that, you can certainly complain to the manufacturer.
Be sure to cut it out when working with the yarn. The risk that the knot will come undone later is too high.