Box API Preflight check on document update (not first time upload)

Hello everyone,

I'm trying to use the Preflight check request you provide in your API to check if a document update to a new version will be successful but it doesn't seem to work properly. Whatever I try to send, it will always respond with SUCCESS: 200 even in cases where I think it shouldn't. I tried for example to send a preflight check with a document rename and the new name was conflicting with an already existing document name but I didn't get a 409. I even tried lots of different things like sending preflight checks for non existing file ids or sending garbage body data but always got back 200. Is that how it is supposed to work? Thanks