Are you in a particularly warm environment? Ensured the heatsink is seated properly? Otherwise I can't really see why the temps are behaving that way. 5.1V input suggests the power supply is fine. ASIC voltage is correct.

I let mine run for about an hour with the tab left open so it would log a good bit of data. You'll notice the frequency is a lot higher at 600MHz but my power draw is like 10% lower than yours with the commensurate efficiency improvement. You'll also notice the temperature is basically flat with a room temperature of about 25 celsius.