I am getting this error with Magento 2.4.3-p2, and only in development (Docker).
When I go to the Admin UI page for Catalog -> Products, I get the following error:
Looking at the AJAX call that failed, I see some bizarre parameter handling:
https://myhost/admin/mui/index/render/key/hash/?namespace=product_listing&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&filters[placeholder][]=true&sorting[field]=thumbnail&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&sorting[direction][]=false&search[]=scsr&search[]=&search[]=&search[]=&search[]=&search[]=&keywordUpdated=false&paging[pageSize]=20&paging[current]=1&isAjax=true
In exception.log, I see the following error:
Array to string conversion in /app/vendor/magento/module-ui/Component/Filters/Type/Search.php
That is, Magento is expecting the search parameter to be a string, not an array as built up on this page. If I fix that, I get an error for the sorting direction.
It is like my HTML or JS is out of date with the application code. But the static assets are freshly generated and I have confirmed that my Magento UI package version is correct, and the same as on my cloud staging site (which does not have this error). Has anyone seen anything like this, or might know what is going on?