We are experiencing similar issues on all browsers for IOS 16. Try setting the value of z-index between 0-9. This solved the problem for us.
.navbar-mobile { position: fixed; top: 0; . . z-index: 9; } section { transition: ease-in-out 0.3s; position: relative; . . z-index: 5; } body { font-family: "Open Sans", sans-serif; background-color: #040404; color: #fff; . . z-index: -1; //(或者嘗試1) }