It should work if you don’t alter the navbar element too much. Test at each stage, each step.
What you can do also is to take the actual one, delete element after element and test, to see where there’s something that makes you older version of Safari bug.
Try also to delete your extra classes, revert to original or no class at all, keeping your structure. And from there, see if it bugs-. If it deosn’t, restyle your element again with new classes.