That can happen to any wheel. It all depends on who and how it was built. I wouldn't throw the baby out with the bathwater here, find a competent wheel builder and have them rebuild it properly. Truing a wheel is only part of the process. More importantly, wheels have to be tensioned properly. I've had 36 spoke wheels brake on me because they weren't built properly. On a tandem, properly built wheels are more important than on the single because of the additional weight and torque you are putting on them