The Romanians take sufficient losses to lose and the Soviets have a surprise attack of rationality and cancel the assault (random event) resulting in a Soviet win. The Romanians were decimating the Soviets but it really didn't matter as the Romanian position south of the bridge in the woods was overwhelmed resulting in sufficient losses to preclude a Romanian victory. Once the orders were changed, the Soviets couldn't lose. Kind of a gamey result but reflective of what could have happened had the Soviet leadership in the early war had any sort of rational thought process.