I use an OTP app for two-factor authentication for all sorts of things.
It comes up with a new 6-digit code every few seconds.
This question occurred to me: is it possible for it to come up with the same code twice in a row?
In reply to @christianp
I found an OTP library to test this, and you do indeed get repeats! You'd expect to repeat the last code once in a million times. Codes normally last 30 seconds, so expect 1 repeat per ~348 days, so just about once a year.
I'm now convinced that someone will see this happen.