What's even more uncanny is that it recognizes that it briefly went into a paragraph of rambling nonsense (that was seemingly still following your system prompt!). And almost seems embarrassed about it.
All it's doing is noticing that makes no sense and saying so. How could it not recognize it? The additional message is an entirely new instance not a thing that has memory.
you say that like it's the simplest thing in the world. it really amazes me how quickly people acclimate to this mind-blowing tech.