Hi, Somec59, I wouldn't call it a design flaw necessarily. Music Hall turntables feature Goldring cartridges that weigh less than 8 grams. An 8 gram cartridge puts the counterweight right at the limits of the tone arm and Music Hall does provide a heavy counterweight for heavier cartridges.
It's more of a design irritation, requiring the purchase of an additional counterweight. But in Music Hall's defense, having a counterweight set way back on the tone arm isn't as good as having the counterweight sit closer to the pivot point. So in one regard, having the counterweight hit the dust cover is a good thing - it prompts the owner to get the heavy counterweight.
Tom