A while back I wrote a thread on a social media website which I no longer use, about this Unicode character, a famously terrible joke, and Christmas.
“ﬃ” is the Latin Small Ffi Ligature. It’s a nice way of presenting two Fs and an I (say, in “eﬃcient”) without the various dots and ascenders mushing together. Most fonts have it, and you see it every day without noticing it. There are versions for other combinations of too. Depending what font you’re using, some, all or none of them may look different to the individual letters
Usually they just look nice and get out of the way, but ligatures can cause problems, say when a passage in a book is supposed to look like it’s written on a typewriter but the typesetter forgot to turn them off. No typewriter has an “ﬁ” key.
And usually they’re added in automatically, rather than being encoded in the text, but sometimes (as in the tweets above) you can put them in explicitly, and that can cause problems when a font doesn’t have that ligature. You might get a box, a font change, “?” or nothing at all.
Which brings us to this cracker joke which you have probably seen go round the internet at least once. It’s not the joke as intended, but it’s not really a typo either—who forgets to type three consecutive letters? It’s “coﬃn medicine” rendered in a font with no “ﬃ” glyph.
This also explains how this error got into the product: almost certainly the joke was proof-read, but in a font where it rendered correctly and made perfect sense. I mean obviously it still wasn’t funny, but it’s a cracker joke, they’re not supposed to be funny.
They are supposed to basically work as jokes, though, and this doesn’t (in any font). “Cough medicine” shouldn’t be in the setup. The first line should be “what does Dracula take when he has a sore throat” or similar. This is one step from “what cough medicine is sort of like a coffin”.
Of course, none of this excuses the fact that when I posted this thread, it was at least the third year this error had appeared, but I invite you to imagine an office of people dismantling boxes of crackers, finding the ones with this joke in it, and switching in a correction without breaking anything.