Repro:

1. Create a new world with the behaviour pack installed
2. Place down a snow layer
3. Right click the snow layer

There will be an error along the lines of: 

[Scripting][error]-ScriptBlockStateComponent | Invalid type passed for block state 'height'

The script is simply increasing the height of the snow layer to values defined in the docs, but results with this error.

What should happen is that the snow layer height will increase and reset, as per the code in the server script. Other blockstates (string based etc.) seem to work fine.

This script functioned last in 1.12.0.28.