Sure there is. It's right here, "at the time fixed for the beginning of the term of the President..." Well, at the time fixed for the beginning of the term for President Obama was held to be eligible. If it turns out that was wrong then he gets removed and Biden is president. Just like the 25th Amendment says.
Re-read post 50. The time limit applies to “if the president shall not have been chosen”, not “the failed to qualify” clause. Hence, the OR