Receiving Workflow Error on required fields when transitioning states

[Nannette Mori]

I created a validator for each of the state transitions.  I have different fields being required at different state transitions.  The behavior is different on some of the state transitions.  For example when I transition to the Done state the screen displays what field needs to be filled out with a red asterisk displaying next to the required field.  But in some of my other state transitions it displays a error msg "Workflow Error, displays the fields that are required, ex Budget source is required, Planned Finish is required.  It seems that you have tried to perform an illegal workflow operation.  If yo think this message is wrong, please contact your jira administrators."

What is causing this workflow error?  I want the behavior for each transition where I have a validator check for required fields to display what is required (if the user has not set the value) by displaying what is required with the red asterisk by the field.

How do I fix this issue.

[Rasa]

the screen is missing on each transition. You have to have validator + screen on every transition where you need to :)

[Nic Brough -Adaptavist-]

This looks like you have put validator code in a post-function. 

A validator should return the person to the previous screen, with a message you define in it (I doubt anyone would have put in "workflow error" and the "illegal workflow operation" sentence into a validator.

Could you show us where these validators are running and what they are? (As in are they scripts or things from plugins?)

[Nannette Mori]

The validator is not in a post function.  It is in a validator function.  If I want the fields to be required at Prioritized State I click on the transition for Prioritized State and add the validator for required fields.  So if I try to change the state to Prioritized it displays the workflow error.  These functions are part of JSU automation.