So i just update my Houdini to 20.0.547 and i found that after i cache my sim (with regular file cache), normally it should just read the cache and do the rest thing, but in this new version it will still sim every frame, even if i create a new box and flag it.
Is it a new version bug or i need to do some extra setting?

Bad update this build still has this bug. Please update to the latest stable build.