Hello, Amiseo,
We apologize for the delay in responding.
The fix will be included in the next update.
Please download the request-quote.php and callbacks.php files from this page https://we.tl/t-Po5lWY5IXV
and re-upload the request-quote.php into the et-core-pluginapp/models/customizer/theme-options/product-single-builder/ folder and the callbacks.php into the et-core-plugin/app/models/customizer/theme-options/global/ folder.
Kind Regards,
8theme team