I have had the knots happen with several different brands. Mostly it was joining two different segments of thread to make a continuous thread. A couple of times, the knot slipped all the way through the machine guides, tension and stopped at the needle. It was a surprise for sure.
To save money, I buy only 1100 meter to 5000 meter cones and accept that it can happen with that large cone of thread. To me it is just inconvenient. Luckily, my piecing is done in bits at a time and mostly fairly slowly so it hasn't caused any major problems for me.