Exactly what I have experienced, I have tried with "thinking set" and saw varying results. An analogy - Each prompt in a conversation felt like I was talking to a different support representative, who missed one or the other part of the overall context, and I had to repeat myself many times. But it's also an inherent human part of me that forgets I'm talking to an AI.

However, I never explicitly told it to "think hard" - I will start doing that. I believe that is the key to making it work consistently.

Thanks!