Pipefy GET request with URL query parameters always returns 400 Bad Request

I’m trying to use Pipefy’s automation to make a GET request to this endpoint:
https://monroneylabels.com/cars/vin.json?single_access_token=MY_TOKEN&car[vin]=MYVIN17CHARS

I set it up in Pipefy like this 

• Method: GET

• URL: (full URL with both query params, as above)

• Authentication: No auth

• No headers, no request body

In Postman and Chrome, this exact URL works and returns 200 OK. But in Pipefy, it always returns 400 Bad Request. 

How can I get Pipefy to actually send the query params? Is this a bug or is there a workaround?