Several Russian commentators have pointed out that the real reason for the postponement is political. In EJ, Alexander Goltz writes (my tr.) that
In actual fact, the Russian-American maneuvers, and even the entire existing system of military co-operation, was not all intended to prepare the armed forces of the two countries for joint operations. However strange it may seem, these maneuvers represented a certain modern form of mutual restraint. With the increased cooling in Russian-American relations, and the growth of anti-Americanism cultivated by Federal television, the Torgau maneuvers were supposed to demonstrate that even if our two countries plan to wage war, they will only do so together, and not against each other. It appears that now the Kremlin does not feel the need for this demonstration.