is anyone facing with depth of field issue for 4.9?

Development Rendering
1

I created a post volume in the scene when I was to tweak in depth of field below the box method. When I turn it on the box, it couldn’t slide and somehow is kinda lock on the slider. Therefore I have to downgraded to 4.8 and is working perfectly unlikely 4.9.

2

I have exactly the same problem

3

I used to have great DOF effect in my scene, after upgrading to 4.9.2, I faced the same issue.
Is there anyone from Epic Games here to help us ?