Zaps work on Test but runs into error when deployed

Question

Zap structure:

1. New Invoice in Zoho Books
2. Shorten Zoho Invoice URL
3. Using Zoho Webhooks, send a Whatsapp Business API message that sends the invoice/summary in Whatsapp.

The Zap runs into trouble on the Webhooks (Custom Request) part. The body of the custom request is in JSON: Zapier Zap body

In the data part: we have a User ID, event name & traits.

The problem arises from the User ID. Zapier doesn't let me have the numerical user id that Zoho inputs, instead, it gives me some placeholder text that is "{{xxxxxxx__contact_persons_detail}}"

Except for the problematic User ID, the rest of the data that got its input from Zoho works fine.

[One other problem I got with the same Zap is that when I use phoneNumber instead of userId, the Zap always run into an error telling me that - The app returned "userId or phoneNumber is required for creating events" - even though I had phoneNumber in the JSON body. This too arise from the same as above :Zapier phoneNumber issue .

Thank you for your time.