Both links have the same active styles and states.(The violetlike colour is not in the css managing havor/active etc. it would just underline them )
I pasted only the “active”/”used” Styles shown in firebug to codepen.
So Firebug/Firefox tell me the colour is #ee7100/rgb(238, 113, 0) where it is obviously not for the “Registrieren” link. The other link is fine. This is just an example and happened in another menue too.