I don't seem to be getting any block physics. Here is the relevant part from my config:

Additional Falling Blocks:
Enable: true
Break Torches: true
# Whether a falling block that is broken by an obstructing block should drop as an item
Drop As Items: false
# When a falling block lands it checks if the blocks around it should fall as well. Can cascade downwards infinitely.
Landed Blocks Can Cause Blocks To Fall: true
# Should a falling block damage players when it lands on them.
Dmg Amount When Hitting Players: 2
Turn Mycel/Grass To Dirt: true
Enabled Blocks:
- GRASS
- SMOOTH_BRICK@2
- DIRT
- COBBLESTONE
- MELON_BLOCK
- HAY_BLOCK
- COAL_BLOCK
- MYCEL
- SNOW
- MOSSY_COBBLESTONE
- SNOW_BLOCK
- PUMPKIN
- SOUL_SAND
- '5882'
- JACK_O_LANTERN

I don't seem to be getting any block physics.

Elaborate - you mean when you place the block from the Enabled Blocks section with air underneath, it doesn't fall?

Ah, sorry. It is working. It seems that if you have gm1 the blocks physics just don't kick in. With gm0 I'm getting block physics.

Yea, you'll note at the top of the config whether EHM features are enabled for creative mode players (which defaults to true), as well as for ops (which defaults to false)