Validation errors not returned properly (CORS issue?)

[usu]

Validation errors (422 responses) are not properly returned in the frontend. The status code is correct, but the payload is empty and in Javascript, the error is detected as "network error". Chrome says, the issue is the missing "Access-Control-Allow-Origin" header.

For example when changing the material list name to something longer than 32 characters:

I think the underlying issue is this one: nelmio/NelmioCorsBundle#124

Symfony throws a ValidationException, in which case the kernel.response event is not processed. As of today, NelmioCorsBundle only listens on the kernel.response event.

Anyone can reproduce? What is weird is that I'm pretty sure this has worked earlier, hasn't it?