ajax error when using browser auto-fill and state dropdown

just started happening. when i use the browser auto-fill feature, the site freezes and spits out an error ( Sorry, there was an error with your request )

The console says:

jquery.js:4 POST https://alpineimageworks.com/wp-admin/admin-ajax.php 400 ()
send @ jquery.js:4
ajax @ jquery.js:4
(anonymous) @ (index):451
setTimeout (async)
(anonymous) @ (index):450
dispatch @ jquery.js:3
r.handle @ jquery.js:3

I tried switching themes and plugins on staging to see if that would fix the issue but was still happening on staging. I enabled admin ajax monitoring on live and tailed the output log and when I went to autofill it triggered this [action] => sunshine_checkout_update_totals which is referenced in the theme but also in the plugin itself:

wp-content/plugins/sunshine-pro/sunshine-template-functions.php
wp-content/plugins/sunshine-pro/sunshine-functions.php

Is it possible that there’s a conflict on this?

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