Battleworld Map syngery activation

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The Battleworld Map synergy activation, which only works on a Battleworld character (i.e. in the current Boss Event, BRB is boosted).

It says (paraphrasing) up to 1 time per battle and once per turn, the Thor Corps will come in and shuffle the board, blah, blah, blah.

This actually activates in the middle of a cascade. So if i match 3, and expect what falls to create another match 3... This activates and messes everything up.

Is that the intention? Or should only activate at the start of the turn.