Mobile responsiveness header 767px glitch

Hi all, when I’m viewing my header at any width, it appears exactly as intended. However, whenever the width is specifically at 767px, there’s this weird glitch where the content ‘expands’ and looks nothing like how I’ve set it. It’s a little hard to explain so I’ve included images of the glitch when it’s at any other width here, and when it’s specifically set at 767px here. I’ve tried creating a brand new header to test it out, and this odd glitch appears even in that new header, and this ‘expanding’ seems to affect everything in the header be it images or text. Is there a fix for this? Thanks.