The combo breaker was a piece of code that checked the gems the computer was about to drop during its turn. If this would result in an extra cascade and you hadn’t had an extra cascade in a while it threw those gems out and generated new ones. Once turned off the computer now gets its gems randomly with no intervention just like we do. this is an explanation I read somewhere else on the boards and put into my own words, so take it as you will
This can lead to a certain bias in people called recall bias where we remember things in our favor less clearly than things not in our favor. So it leads to complaints of “the computer always gets 4 of a kind matches dropped in and I never do!”. On the lowest difficulty this code remains in place ensuring that the “random” drops favor you more than the AI.
Interestingly enough (and probably just another form of bias) it seems like I am seeing a lot more dropped in combos on both sides since increasing the difficulty than I did previously.
Hope that helps!