I run into knots once in a while and I use a fairly wide price range of yarns. I just cut out the knot and treat it like I'm joining another skein. Luckily, though, the yarn knotted on is pretty much the same as the old stuff.
I think more than one knot in a skein or more than one dye lot is unacceptable. You should totally write to Caron and let them know what happened.