If Xpath works in the browser it should work the same via GET request.
However, maybe you are mixing GET requests and browser version in your
test code. That results in empty value when you send Xpath query through
GET request.
The point of using GET requests is to save usage of hard disc and RAM space, So get
request is saved only in RAM memory and that is the reason why it works
faster and saves hard disk and RAM space too,
Once you send GET request you have to follow it with Xpath GET request.
If you use SAVED CONTENT between you will loose initial GET request and
Xpath get request will return empty string because it no longer works with
last sent GET request, since you interrupted it with "SAVED CONTENT".
Im not sure that this apply to your case, since you did not provide a test code.
But it might be possible that you are actually mixing GET requests and
"SAVED CONTENT" - so its not working as expected
If you work with GET requests, there is no point of using "SAVED CONTENT" since
"SAVED CONTENT" is usually used for saving data to hard disc and breaks last GET
request. So if you work with GET requests do not mix them with browser actions like "SAVED CONTENT"..