Laravel+Vue. Caching problems

I create Laravel+Vue simple REST API web-app.
In Vue component I have a method with an api request.
I simplified this to see the core of the problem:

phpValidate() {

axios
    .post("api/validate", self.programmer)
    .then(function(response) {

        console.log(response.status); 

    });
}

In the controller I have a method validateIt(), which handle this "api/validate" request.
It returns:

return array('status' => $status, 'data' => $data);

The $status can be equal to 200 or 422, depends on the input data.

The problem is that from some point, it began to return $status of 200 always.
Even if I delete all the code from the method validateIt() and just leave two lines:

$status = 422;
return array('status' => $status);

I still receive 200. If I delete the whole method in controller, it gives an error 404.
So, the route and function name is correct. When I put it back, I can write there whatever I like, it doesn't have any sence - it still returns 200!

If I use debugger, I can see that at the end of validateIt() method it returns 422.
But, when I get the response in phpValidate() I see again 200.
Unbelievable!

I tried:

npm run dev

and

php artisan cache:clear

doesn't help!

Also I tried to restart the server and use different browsers, doesn't help.

via Chebli Mohamed