I'm playing on medium since the latest patch, and "default_AI" before.
I don't fully understand what's happening myself, as it's not happening everytime.
Most RTS games I manage to do good enough to win without many problems.

But sometimes, while the initial match goes on as usual - me capturing some build points and building recruiting centers and production buildings and occupying choke-points - at some point the AI seems to be able to quite quickly muster a very large army of small units (mostly troopers, some shamans and bazookas, but also some hunters) and overwhelms me with it.
Now, in principle I should have the same or even more ressources, since I usually hold at least 50% of the map, but when it starts, I can't keep production up the same way as the AI does.
It might be that countering the blob of death is easy with the right tactics and abilities (which is also why I ask), but it seems that esp. in the early game you will likely not have the units/abilities to counter the blob so easily.

Now, I'm not saying that the AI is cheating or that there is some bug, but seeing that the AI seems to have NO problem constantly producing a ton of infantry, while I'm out of ressources fast, one could get the impression.
Hm, I will try to gather some more info...