Thank you for your response.
If further tested and here are my findings.
1- Create two versions of any site (eg: Staging or Production) or take two sites A & B.
2- Install Similar plugins and themes on both sites.
3- On Site A, create a gravity form with chained select. It will work fine.
4- On Site B, Create another gravity form with chained select. It will also work fine till this step.
5- Now make some changes on gravity form on Site A and then Export that specific form from Site A.
6- Import Exported form in Site B (form exported from Site A in step 5).
7- Chained Select will stop working on Site B on all forms. It will not work on new forms either.
Here is a list of all plugins and their versions, we have on site.
Advanced Custom Fields PRO,Version 5.9.1
All In One WP Security,Version 4.4.9
Builder PowerPack,Version 2.20.0
Custom Post Type UI,Version 1.10.1
Duplicate Page,Version 4.4.7
FacetWP - Beaver Builder,Version 1.4
Gravity Forms,Version 2.5.16
Gravity Forms Chained Selects Add-On,Version 1.5
Gravity Forms Multilingual,Version 1.6.2
Gravity Forms Webhooks Add-On,Version 1.5
Page Builder,Version 22.214.171.124
Page Builder - Themer Add-On,Version 1.3.3
SearchWP WPML Integration,Version 1.6.6
Snowberry BB Addon,Version 1.0
Ultimate Addon for Page Builder,Version 1.34.2
WooCommerce Gravity Forms Product Add-Ons,Version 3.3.23
WooCommerce Print Invoices/Packing Lists,Version 3.11.4
WooCommerce Stripe Gateway,Version 6.0.0
WP Engine Smart Plugin Manager,Version 5.10.1
WP Mail SMTP Pro,Version 3.2.1
WP Rocket,Version 3.10.6
WPML Multilingual CMS,Version 4.4.12
WPML SEO,Version 2.0.1
WPML String Translation,Version 3.1.10
WPML Translation Management,Version 2.10.8
YayMail Pro - WooCommerce Email Customizer,Version 2.8.1
Yoast SEO,Version 17.9
In our case, we have staging, dev and production sites and with same plugins and themes. Right now chained select is broken on Dev site, after exporting form from Staging and importing to Dev site.