JIRA Batch Notification with Customfield Value in Subject

[Info INOHA]

Hello,

I would like to display a custom field value in JIRA batch notifications.

Without the Batcher it is working with:

$issue.getCustomFieldValue($customFieldManager.getCustomFieldObject("customfield_10228")).toString()

but not in batch notification.

Then I found this: 

2020-11-23_14-28-20_Adding custom fields to emails (batched notifications) | Administering Jira applications Data Center and Server 8.15 | Atlassian Documentation

and I tried to display the notification with: 

${customFields.get('10228').getValue()} 

or

$customFields.get('10228').getValue() 

or

$escape.apply($customFields.get('10228').getValue())

all this not working. In Email I see this code in subject as it is.

Please can someone help?

Thanks

Thomas