Gravel animation is slow when it falls and breaks on bottom slab.

To recreate this place a bottom slab under a block holding up gravel and break the block holding up the gravel.

The block will appear in front of you but the player is able to walk through the block and no matter how many blocks of gravel fall only one block appears. Eventually the block will break producing the proper drops.

I have a video on my playstation but I am unsure how to get it from there to here