I was fighting the boss on level 5-8 and on my last hit the boss died. Normally all movement in the board stops as soon as all units in the whole level have died, so any cascading hits won’t go off. However, in this case at the moment the boss died there were zero possible next moves left on the board, triggering a reshuffle, creating a small cascade. Based on the normal behaviour of the game to stop all movement in the board when you’ve defeated all units, I would expect the reshuffle not to happen. That also feels logical if the victory condition for a level is ‘defeat all units’, opposed to ‘defeat all units AND have at least 1 possible next move left on the board’ which the observed behaviour more matches.
On normal levels it would not matter that much I guess, but it might matter on event levels where time is a factor in your score (and ranking).
I’ve been playing for a while now and this is the first time I saw this behaviour. I’m not sure if I never noticed it before, or that I just never ran into the situation where there were no more possible moves left on the board when defeating the last unit in a level. I can’t really replicate it, due to the randomness of the board.