Please, provide your site admin access (insert the site credentials into the Private content block under the message area), describe the steps to see or reproduce the error and confirm the permission for plugins deactivation, switching to the parent or default theme. This testing may take up to 15 minutes. You would better make the full backup of your site.
I have found the error on the product grid, and when I disabled the child theme and plugins this warning has gone, please enable the plugins one by one to detect which one causes the problem.
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