Sorry it was not one time but it happened easily 5-10x during the past few days on different topics and prompts and I didn't store them. It felt like when pushing the model on some specifics in some niche topics in German (I have been prompting in German and the model responded in German). It was the acutal output and not the thinking traces and it was through the API. I jokingly asked it what the character meant and it didn't even make sense in the context so it seemed like random chinese characters.