Smooth time not really working

[T1gg1]

I control my blinds with the blind controller, if sun is in the window, the blind moves to position 50.
I have a Luxsensor and if lux is under a value of 40000, the overstear rule move the blinds to 100 (open).
I have a smoothtime about 20 minutes.

My problem:
Sometimes my blinds moves every minute. But if I try it manually by changing the lux via a message, it says 'block change to 0' even after 2 hours.
Is it random or is my config wrong?

Thank you