Buttons in iOS app don't respond to touches around the edge of the screen

I'm relatively new to iOS development, but I'm having a go at working on some open source code for an old game that used to be pretty popular (Eden World Builder)

I've made quite a lot of progress in cleaning up the codebase, making small changes. But there's an issue I can't seem to fix. Every button in the game will not respond to taps around the edges of the screen. If a button is in the corner of the screen, you will have to tap towards the bottom of the button.

I've tried to move the buttons away from the edges, and they work, but that isn't practical for use. So there's something preventing the edges of the screen from registering button taps for some reason, and it doesn't seem to be anything to do with the button target areas themselves.

One thing I've noticed: This game is currently on the App Store, even though it hasn't been updated since 2015. In the App Store version (Which is built from the same code that I have) the issue doesn't occur. It must be something to do with building it in a newer version of Xcode, right?

Any assistance would be very helpful, this has been frustrating me for weeks now. Thanks