Your problem is in this class in the file css.css
It is affecting some elements within your .gtco-nav
* {
transition: 0.5s !important;
transition-timing-function: linear !important;
}
This transition: 0.5s !important
is doing this "delay" in the transition. If you put 0s in place of 0.5s, you will see that it solves. But as it is in the *
universal selector you will have to see the best way around this so you do not lose the effect where you do not want to.
OBS: The selector *
has a bad worm-time so it should look more than 0.5s, this is the worst selector when CSS has to read the entire file to place the class. Law more here link