Missing question mark in URL

[andrescastiglia]

When I define a URL with question mark, the request removes it, for instance:

*** Settings ***
Library    REST    https://acastiglia.testrail.io/index.php?/api/v2/

*** Keywords ***
Wtf
    GET    /get_case/1
    Output    request

The output is

{
    "method": "GET",
    "url": "https://acastiglia.testrail.io/index.php/get_case/1",
    "scheme": "https",
    "netloc": "acastiglia.testrail.io",
    "path": "/index.php/get_case/1",
    "query": {},