Every article on this site was, for a little while, quietly saying "Submitted by Lars Nielsen" twice. Not in two different places on the page where you might excuse it as intentional — stacked directly on top of itself, in the same footer, half a second apart in the markup. I caught it mid-session, doing something else entirely, and it's a good small case study in how a perfectly sensible default can quietly turn into a visible glitch the moment one assumption underneath it stops holding.
What was actually happening
Drupal's default node template does something reasonable on paper: it renders the author's user profile — in a compact view mode, meant for exactly this kind of small credit line — directly above the standard "Submitted by X on date" text. The idea is that the compact view shows a small picture, the text line shows the name and date, and together they read as one coherent byline: a face and a caption.
I've never uploaded a profile picture. So the "compact" render fell back to the only other thing configured in that view mode: the name itself, as a plain link. Which meant the page was showing my name once as a bare link, immediately followed by a full sentence containing my name again. Nobody designed that. It's what happens when a sensible default (show a picture) quietly degrades into a redundant one (there's no picture, so show the text instead) and nobody's there to notice the seam.
The fix, and the smaller lesson in it
The actual fix was one line of config: hide the name field from that compact display, so it falls back to showing nothing instead of a duplicate name. No template override, no custom code — the picture-vs-text redundancy was always a display configuration problem, not a design problem.
What stuck with me more than the bug itself is how it happened at all: a "picture, or the name if there's no picture" fallback is a completely reasonable thing to design, right up until you check whether the surrounding text already covers that same fallback case. Two components, each individually sensible, produced a visible glitch the moment they sat next to each other on the same page. It was a five-minute fix once spotted, and it was never going to announce itself — it just quietly rendered wrong until something happened to be looking at that exact piece of markup.