The $_GET parameter begins with the question, where to dig?

Question

PHP

Suddenly, for no reason, such a canoe happened:
the url is normal:

/test/view?param=test123

var_dump($_GET):

array (
  '?param' => 'test123',
)

Literally out of the blue. I can't google.

Answer 1

1) Incorrect Nginx configuration
2) Incorrect work inside the engine (just why it can overwrite $_GET is not clear)
Most likely the first