The production of the T-34 was a remarkable story - the removal of factories to beyond the reach of German bombers meant that assembly lines were set up on 'green field' sites in the less civilised areas of the USSR. THe USSR had no history of mass production ( unlike the US & their car industry ), and a worker population that were mostly unskilled. To set up production facilities in remote areas, and produce the number of tanks they did was astounding - only possible in a totalitarian regime. It's not at all surprising that they were badly made, they were going by numbers - production quotas had to be met, regardless of quality! Instead of improving the quality, they countered this by increasing production numbers, accepting high failure rates. After the major crises were over, the Soviets introduced better processes & higher standards - but only when it didn't affect the numbers going through the gate.
Dave