Use below transform instead and make sure ‘whenChanged’ attribute is defined in the schema of your AD application,
{
"name": "iSeries DateFormat Transform AD whenChanged",
"type": "dateFormat",
"attributes": {
"input": {
"type": "accountAttribute",
"attributes": {
"attributeName": "whenChanged",
"sourceName": "Active Directory"
}
},
"inputFormat": "yyyyMMddHHmmss",
"outputFormat": "ISO8601"
},
"internal": false
}