Why does Lorenza Nav links error occur when adjusting screen size?

So Im modifying my clients theme and I have changed the breakpoint multiple times for the transition from desktop to tablet in order for the nav links to not become messed up when the window size decreases. I go through it in the developer tools and everything works great and the breakpoint is properly set but then when I turn off dev tools and try to decrease screen width this occurs. Any help would be very much appreciated.

Heres the breakpoint i changed

$break-tablet: 850px; //Changed from 769px, the reason was to accomodate for the larger font.