It seems most links in the logged user interface are actually an anchor tag followed by a button tag (Inbox, Trending, New, New Publication).
This is invalid HTML, and nesting interactive elements multiplies the number of times one has to press the "tab" key to get to an interactive element when navigating with a keyboard.
A screen reader (like NVDA) would announce "Trending, button, link" twice, which is confusing.
I'm not sure the buttons are really needed, it seems in most cases they are used to lend give links a button appearance.
If so, do not forget to add style for the focus state of links.