Title. Idk if this is on purpose, but after entering a sleeping ogre tile for the first time where you have the option to steal, ambush, or leave, I can never trigger it again. Even with max stealth and perception, and the tile saying it's a sleeping ogre, it will always instantly trigger the ogre fight after the first ogre encounter. Is this a bug, or is it made on purpose that you can only steal/ambush an ogre once per playthrough?

Yeah, it's only a one-time event each playthrough. You'll get more similar chances to get Gold in later Map Areas, which aren't one-time.