We recently upgraded from magento 2.2.7 to 2.3.3 We have an issue when we click on any filters at PLP. The filter parameters are getting stripped from the URL and it redirects back to Original PLP page.
For example when we click on size filter it should go to http://store.base.url/dresses/?size=10. But it redirecting back to httP//store.base.url/dresses/
Ran into the same issue with 2.3.3. Its a known bug and has been fixed in 2.4-develop to my knowledge. Here is the commit for the fix.
What your gonig to want to do is a composer patch using the diff of this commit. If you follow the steps in devdocs for the "Custom Patch" here.
https://devdocs.magento.com/guides/v2.3/comp-mgr/patching.html
This is what has worked to resolve the issue on our projects.
