Validator on issue creation: impossible to retrieve values

[Former user]

Hi, I'm trying to validate input by users on Jira Service Desk new requests using your plugin code-runner. On "create issue" transition I added a new Inline script Validator but when I try to check values inserted by users I always get a "no such property: xyz" Error right after the user click on "Create" button. I'm trying to access values of issue, using $issue binding; but if I try to serialize $issue I get only the summary the user entered (and every other fields is missing). Is there something I'm doing wrong or misunderstood? This is the output of serialized $issue and $transientVars: issue:prova transVar:['entry':com.opensymphony.workflow.spi.SimpleWorkflowEntry@42453581, 'issue':prova, 'configuration':com.opensymphony.workflow.config.DefaultConfiguration@3a574308, 'context':com.opensymphony.workflow.basic.BasicWorkflowContext@15ea5e08, 'originalissueobject':null, 'actionId':1, 'issueProperties':['request.channel.type':{"value":"portal"}], 'currentSteps':[], 'pkey':'XXX', 'store':com.opensymphony.workflow.spi.ofbiz.OfbizWorkflowStore@58942cd8, 'descriptor':com.atlassian.jira.workflow.ImmutableWorkflowDescriptor@13a38ff1]