If you use a workflow to invoke a business process, and the variable populations are blank, they will not be treated as blank by field rules present.

I originally thought that the CSS was being ignored by the field rule when invoked by a workflow, but after further trouble shooting, I saw that there was a very large amount of white space inside of my form when placed into the repository. This white space is actually my single line values that were supposed to be removed from the form with the field rule I attached below.

It seems like Laserfiche forms can't recognize a field as blank if it was populated with a blank value from a workflow.