Saving a custom form Errors with: "Cascade Rule Match Value 'value' is invalid with associated parameter, 'Field Name'"
The field name in the error is using custom display logic.
In the Custom Form find the field name from the Error and select it's "Section Break" Choose "Edit Logic"
In this situation, one of the Logic lines did not have a value selected. Selecting an appropriate value corrected the error. Deleting the Logic Line will also correct the problem.
It was discovered that the 'Value' in the Error message had recently been renamed which caused the Logic to be incorrect. Correcting the logic resolves the issue.