I just purchased a new wall-mounted mag strip. Before hanging it, I tested it by putting a few heavy-ish/long-ish knives on it; they held securely, but it was easy to spin them in place by gently nudging the knife's top or bottom. Furthermore, knives exhibit a tendency to spin toward a horizontal position if they aren't attached nearly vertically. Is this normal for a mag strip? Obviously, overly-strong magnets are bad because they require too much effort to remove the knife, but I'm worried that the magnets in the strip which I received are too far on the opposite side of the spectrum.