I was solving 1610H - Squid Game, and after submitting, I thought that the TLE verdict that I got is mysterious and I didn't know why. But after I changed language to C++17, it comfortably passed in under 500ms. And I changed it again to C++20, the result is similar, hinting that my code might be correct.

The three submissions should be identical except languages. 328699971 328700051 328700454

I'm not a compiler expert and I'm too lazy to construct a smaller breaking code, so I'm just posting an example here.

When I saw this comment, I wonder how often this has happened. After searching through the list of contests manually, I conclude that this has not happened since the inception of Codeforces.

The closest moment before is probably September 2022, where the only rated Div. 1 round is CF Global Round 22 on September 30th, 2022 (where I was a tester).