I’ve logged into your sandbox site and can immediately see the problem.
You have a file or possibly files from version 3.1.1 still on the server, not replaced by the ones from 3.2.0.
You have said previously that you collected a set of all the changed files from soon after that release, the ones I provided here. Can you send me that set so I can see if that is where the wrong files came from. As I recall there was a wrong one I uploaded at some point. I suspect that is the cause of all these issues.