unless your using saves from before 0.30 that cant be an issue as i have and i still got to do the enemy event, im real quick gonna check this. plus you meet the mysterious enemy if you chose the bad ending at the very start of the bad end when you steal the green gems, he's the guy who tells you to give them to him. i havent done it in a long time so theres a chance hyao changed some stuff in it but you meet him right away, plus maybe?
ok yeah i check it is in the lizards treasure event log, all it says you gotta do is sleep at the ruins on the regular route but theres an extra thing if i remember correctly. you need rhot to have a certain amount of like which could also be causing something so maybe thats it?