I recently read of the USS Tang and the USS Tullibee both of which were sunk by their own torpedo.
The three major design defects with Mark XIV torpedoes were that they ran much deeper than set, the magnetic exploder was not reliable, and the contact exploder was not durable enough and didn't explode if the fish hit the target at close to a 90-degree angle.
USS Tang was hit by her own torpedo, which was seen to be doing a circular run. While weather didn't allow seeing it, it is probable that the
USS Tullibee was also hit by a torpedo that did a circular run. The torpedoes that sank the two boats were obviously defective, but I'm not aware of this being a design defect. Not that I'm anywhere close to having a historian's knowledge.