Query param is not being removed

I am running a Run TestCase TestStep and not passing in the param lastNames, however when I go to run my test I am getting an empty array with a 200 status code because lastname is not being fully removed, am I doing something wrong... I am not passing in the full url, that is done on purpose I also have the correct headers just not showing them here. the issue is in bold.

Raw Request:
GET ***?startDate=2018-04-11&marketingAirline=HA&flightNumber=10&origin=HNL&lastNames=&confirmationCode=OJENVL HTTP/1.1

Raw Response:

HTTP/1.1 200
Content-Type: application/json;charset=UTF-8
Date: Tue, 10 Apr 2018 15:26:14 GMT
Server: nginx
transfer-encoding: chunked
Connection: keep-alive

[

]

I have attached a couple of screen shots to show that nothing is being passed in and yet lastNames is still appearing in the query sting above. The only way that I've gotten this to work is if I go delete it at the project layer and then add it back in however it is random. I'm curious if it is how the .yaml is being imported in and if a required field is coming through. Any help would be great. 

Thanks,

Andrew