Invalid Argument Exception when saving a view using a custom filter handler
The problem here is that there is no schema definition defined for the new custom filter.

You need to create a file in config/schema/YOUR_MODULE.views.filter.yml

With the following definitions with the machine names to match your specific setup.

views.filter.YOUR_VARIABLE:
  type: views_filter
  label: 'Example'

views.filter_value.YOUR_VARIABLE:
  type: views.filter_value.in_operator
  label: 'Example'