How do I set a Multi-level cascading select field on jira based on a field in zendesk.

Currently I was able to successfully sync from jira to zendesk (see Set Multi-Level Cascading Select in JIRA Based on Fields in Zendesk) but I want to sync from Zendesk to JIRA.

I am using this add-on for Jira for the Multi-level Cascading Select field: https://marketplace.atlassian.com/apps/5008/multi-level-cascading-select

Here is the setup which is working to sync from JIRA to Zendesk:

JIRA Outgoing Sync:

replica.customKeys."Location" = issue.customFields."Location"?.value?.value

Zendesk Incoming Sync:

issue.customFields."Location"?.value = replica.customKeys."Location".join(",")

This is working but I want to now update the Multi-level cascading select field in Jira from Zendesk however everything I have tried is not working. 

When I do send from JIRA to zendesk, here is how the location comes in:

"customKeys": {
      "Location": [
        "Broadband",
        "AAFES",
        "Mountain Home AFB"
      ]
    },

I need to be able to set this in JIRA based on what I have in Zendesk which is a text field with a comma-separated list of values, ie. "Broadband, AAFES, Mountain Home AFB"