VMware is aware of this issue.
A resolution for this issue is being evaluated for inclusion in a future release.
To work around this issue, perform the following steps:
- Use the string field instead of an array of string in the custom form and make it hidden.
- Add a generic multi-select field in the custom form and fill it with values as you would fill the array field.
- Bind the value of the text field with the value of the generic multi-select.
After submitting the values will be sent to the back end as a comma separated string in the text field and they can be parsed and treated as an array in the workflow.