The "Zephyr Teststep" custom field is not supported via migration

Hi!

I want to migrate Zephyr Squad from server to cloud. I know that Zephyr is JCMA supported (https://support.smartbear.com/zephyr-squad-server/docs/get-started/cloud-migration-guide/via-jcma.html). However, when I try to test the migration and I download the report I get an error like the one I mention on the subject for all issues that has a test associated with it. That test (or tests) have specific steps. And these steps are stored as CF in the jira server. I know that the specific CF is a CF created by Zephyr and it's not supported on the cloud. So my question is what happens when I'll migrate the data to cloud? Am I going to lose all data from the steps? 

The complete message I'm getting on the xlsx report is "The "Zephyr Teststep" custom field is not supported via migration. The value for this issue will not be migrated."