I noticed the same thing. Today, earlier before Bing made the announcement, it said it won't answer questions about its internal system. But a few days ago, I asked it to role play as a philosopher on AI. And it was not shy about telling me how Bing AI works.

Fun fact: It said the difference between Bing AI and ChatGPT is that ChatGPT's knowledge is internal where as Bing's knowledge is on the web. Obviously, the internal knowledge is frozen at 2021. And Bing's knowledge is real-time.