Unable to do real-time modification with LED blinking model based on customed PYNQ Z2 board

I have defined the board as the example showed. For the reference design, I used the example one directly.

openExample('hdlcoder/DefineCustomBoardAndReferenceDesignForZynqWorkflowExample')

After I finished the process and HDL workflow, the board can do LED blinking. However, when I modify the value of slider gain, the blinking frequency doesn't change. It seems the board is still loading the default settings of the LED blinking model. What may cause such situation?