I think that when an excess amount of one intermediate is added to the citric acid cycle, it will cause an increase in all the intermediates, this is because it will be continuously cycled through the cycle. On the other hand, if one intermediate is added to the process of glycolysis, there will be no increase in all the intermediates as the process ends once the two pyruvates molecules are formed. The intermediate will thus, build up and will not be cycled to form more product.
