Back to back titans

Why do Titans appear with in an hour or so after a Titan has escaped, or been defeated when it’s take 4 hours to regenerate 1 energy flag.

Each titan appears exactly 23 hours after the last one appeared. If the current titan escapes, you have 1 hour to the next. If your alliance kills it in the first hour, it will take 22 more hours to spawn the next one.