Do the request headers always match the response headers?

I was trying to get GitHub Commit Success or Fail data from GitHub Website.

so I sent request that include timezone cookie in request headers and got response result in accordance with the request headers. anyway, It's successful on my mac environment.

the thing was on my AWS EC2 instance. I cloned my codes from GitHub to my instance and executed it. but It wasn't same result between my Mac and AWS Instance.

I knew that was about timezone. so I solved problem by changing the timezone of my instance.

sudo cat /etc/localtime 
TZif2UTCTZif2UTC
UTC0

sudo rm /etc/localtime
sudo ln -s /usr/share/zoneinfo/Asia/Seoul /etc/localtime

but I've still had some question.

1. is it possible to have different result between request headers and response headers?

2. if so, why there are different?