Yep. I have a set of 05 Byerlys and on the second time out the knob fell off while in the board rack. One of our chicks actually saw it fly off and land in the water. Gone
I called Hyperlite and they sent me two complete boa kits. It took about 1 week to get. I use a very small amount of blue locktite on the treads of the small screw before putting the knobs back on and no problems so far. They have stayed on for about 6 months riding 1-2 times a week. I check them once in a while, but their always tight.