Deluge Error: "Data type of argument of function 'get' did not match required type [BIGINT]" when working with Lookup fields

Hi everyone,

I’m facing an issue in Zoho CRM Deluge while working with lookup fields.

Setup:

Module: Monthly Bills

Field: Customer (Lookup → Accounts)

Module: Laundry Orders

Field: Laundry_Account_Name (Lookup → Accounts)

Field: Expected_Revenue (Currency)

Field: Order_Status (Picklist)

Use Case:

I created a custom button that:

Fetches Customer from Monthly Bills

Searches related Laundry Orders

Filters Delivered orders

Calculates total amount

Problem:

I get this error:

Data type of argument of function 'get' did not match required type [BIGINT]

Issue Details:

When I do:

customerField = bill.get("Customer");

customerId = customerField.get("id");

Sometimes it works, but sometimes it throws the error.

Observation:

Lookup field sometimes returns:

Map → {id, name}

Sometimes returns:

Direct ID (BIGINT / string)

Because of this inconsistency, .get("id") fails.

Question:

Why does Zoho return lookup fields inconsistently?

What is the correct way to safely extract lookup IDs in Deluge?

Is there a recommended pattern to avoid BIGINT type errors?

Any help would be appreciated.