Sorry for the delay.
The reason for this not working is a timing issue where the casc solution is initiated before the value is set in the hidden textarea. When setting the value in the textarea, spjs-utilty.js was not aware of this field being a “casc” and therefore did not trigger the correct function.
This was set up for the single line of text, but not for the textarea.
I have fixed this in spjs-utilty.js and will publish a new version later tonight (October 25).