Whilst that is true as a general statement, I find it hard to see how such a problem would go away when the 'suspect' ring was broken, in the manner described by the OP.The fault might be on a different ring to the one that appears to have the fault. The trip being caused by some of the current from a load on the ring you suspect is the faulty ring finding an alternative route that bypasses the sensor in the RCD that is tripping.
Kind Regards, John.