Gravity Forms Zoho CRM plugin not passing some fields

I use the gravity form zoho plugin to push data from my lead form into my lead page in Zoho CRM. Everything was working file for about 6 months. Suddenly on Oct 1st, some of the fields are no longer getting passed to Zoho. The fields with the problem are custom fields that are dynamically populated. Referral URL and gclid. I can see that the fields are being populated in the gravity forms entries. But for each entry, only the standard fields (name, email, company, etc) are getting pushed to zoho. The URL and gclid fields are empty in zoho.