Link colours go very wrong

So i am working on a template for a wiki.
And something realy strange happened. I cant tell at which pint, but some links changed colours, but as i looked it up with firefoxtool and firebug the calculated value was another colour.
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The Example for 2 links is here

https://codepen.io/Vironic/pen/xLYEpE

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.
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So i tryed removing the colour styles for the links. And what happened is this.
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So the correct link changed colours to default and the corrupted link stayed that way.
So does anyone have an idea?
Help very much appreciated
Thank you