Please deactivate all the 3rd party plugins and activate only theme-required plugins on the site and then check the issue. I am sure your issue will be solved. Then, activate the 3rd party plugins one by one and check which plugin is creating the issue for you.
Otherwise, if the issue still exists, then keep the 3rd party plugins deactivated and let me know I will further check and give you a possible solution. Also, switch the child theme to the parent theme.
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