You should raise the hotspot to ~90F and keep the ambient around ~80F. I don't know why she does that, maybe just something she likes doing? Do you notice her move to a hide when you turn a light on or do you think it is when she see's you? I think it may be the act of turning on a light or movement that prompts her to move, not just the sight if ya. They are more active at night so that will explain why she only does it in the evenings.