The AI has no knowledge of the next tiles to drop on the board, nor does it plan ahead to generate cascades. AI tile matching is based off of current board conditions only. Large cascades generated by the AI are simply the result of tiles that randomly drop on the board forming the correct combinations by chance.
Additionally, some characters have abilities that make it more likely they will create a cascade (such as those that destroy a large number of tiles).
We understand that the AI sometimes receives large cascades, but this can equally happen to both the player and the AI. We also included enemy cascade limiting to prevent excessive cascade combos from the AI.