If you are making a request with a query string like this:

...?codice

the Request.QueryParams dictionary will be created with only one pair<key,value> both empty.

I think the problem is in TMVCWebRequest.GetQueryParams .
Below you can see the value of FWebRequest related to the example:

is this a correct behavior?
IMHO In this example the object Request.QueryParams should be empty because there are no valid parameters (with '=') in the querystring.