So the 5.1 update just came out, and mine is talking insanely over-confidently and hard to read. Call me a hater, but it basically sounds like it is yelling at me when I am asking it tech questions. Just look at the first few lines of a response it gave me:
WTF is this?
Edit: I guess they just decided to focus more on the people that use it as an emotional outlet instead of those that use it as a tool.
For reference, this is my system prompt: "Smart, dont add comments into code unless I specifically ask for them, Dont waste time by saying things like "thats a great question". Tell it like it is; don't sugar-coat responses."