nav-tabs its come to down
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Might be referring to the broken clearfixes on v4 navs?

enclosed the issue image
Same behavior in Chrome browser (Version 45.0.2454.101 m)

using a display: inline-block on both the <a> and the <li> wil fix this issue somewhat.
Now I run into the problem that there is spacing between the list items in the HTML file which I removed by using comments. Link to Stack Overflow
Also it seems there is no border-bottom on the last <li> item.

Can't dig to it deeper for now. Someone can follow up on this?
Justified navs in general were deliberately removed (see #17631), although no reasoning was given at the time.
@mdo Could we get an explanation for why justified navs were removed?
Justified navs and button groups were super bugged out in Safari when you'd resize your browser.; things would break until you refreshed. Rather than work around that, I'm pushing for us to implement these options in flexbox for more control, albeit with less browser support (sorry IE9).
Example usage in the docs coming in #21201, but not in a separate /examples instance.
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@mdo Could we get an explanation for why justified navs were removed?