Layer activation with Pre Roll

Hi team !

I have part A and part B.
I set 2 bars for Preroll.
So I want to start part B with the 2 last bars from the Ppart A.
I would except that the layers from part A would be activated on the 2 last bars but only layers from part B are activated.

That is questionable. Part changes may cause plugins to take time to adjust, also when preroll is running, I usually prepare for what is to come, not what is before. Your mileage may vary.