Controller "A" button unresponsive at certain angles

I’ve just bought a new Xbox One controller (the latest version with Bluetooth and jack) and after using it for some time I discovered the “A” button is unresponsive when pressed at certain angles which happens to me all the time when I play games. As the result, the press is not registered by the game/system. I read all over the web I’m not the only person with this issue and it might be a design flaw and replacing the controller will not help so I’m eager to just open it and maybe do something inside in order to fix this issue. Otherwise I will just refund it and stay with my old X360 controller that still works better because all the buttons just-work™. I can upload a video to show the issue but it’s basically the same issue that is often brought up about the Elite Series 2 controllers (would love to post some links but I can’t - the post editor doesn’t allow me to). Do you know if I can do anything to improve the responsiveness?

I’d definitely check the rubber pad underneath the controller buttons, might be broken, visually check if the rubber is okay, and if the black pads are still in one piece. I had a few ones, that cracked for some reason, so it is definitely worth checking out.

Thanks for advice. Do you think a brand new controller may be broken in this way? I still have the right to give it back and get a refund even without providing any reason for about a week. It’s also on a warranty for 2 years. I’m not sure if opening it up will void both of these rights. That’s why I still hesitate to do that and I’m looking for a very confident answer. Otherwise I will return it and never try Xbox One controller again since this is a safe approach that will at least give me the money back, especially if the chance to get the controller fixed by myself are low.

Yes. It is possible that it is broken out of the box. It is a rare occurence, about 0.2% of all sales are DOA or broken in some way. The reasons vary - might got broken in transport, or in factory something happened. Back in 360 slim days, i was involved in buying and selling those to the shops. And we had broken x360 out of box every bout 300-500 console. Those things just do happen.
Opening a controller WILL void your warranty (unfortunately). If it is still on brand new warranty - just get it replaced. I would also avoid the black or white controllers, because they are much higher volume item than lets say gray-green ones. I have mine 3 x1s controllers (those new ones as you say), i play with them every day and they are fine. Ofc on the internet some of the news of any flaws will be overblown on the internet. Yes they had issues on the 1st iterations on the x1s controller, but as far as i am concerned - newer ones are hella fine.