Jim,
I am wondering if you installed the fix for force pools that Loki100 referred to above.
I started a new game as Russia using that fix, and the problem you have been describing did not seem to appear, even seven years into the game. The number of Corps, divisions, and brigades I could build as Russia remained strictly limited, and only increased when I was able to suddenly build two light infantry corps. There has been no change in tech, I still do not have rifle muskets, so maybe that is the key.
I did fight a big Chinese stack around Vladivostock, but that stack was in no way comparable to the size of the stacks you ran into. Of course, you were fighting in the heartland of China, not the fringes.
Unfortunately, I deleted the Russian game by error.
But, I am going to start a game as England, with Loki's fix installed, and see if I run into the same situation with the Indian divisions.
Thanks for your detailed reporting on this issue, and I very much enjoyed reading about your epic battle in Canton.
Best,
Vaalen