This has been always been a problem for me in pretty much every J or F seat I've flown: UA 744 (F), MS 77W (J), NH 788 (J), AA 32B (F), AV 333 (J), BA 744 (F,J), CX 77W (J), JL 77W (J), and JL 772 (J) . In fact, this is what has kept me from getting a good continuous session of sleep on all the 5+ hour flights that I have had a lie flat seat. There was only one occasion where the temperature was cool enough that I just felt like I had the best sleep of my life: a United 757 transcon flight from JFK-SFO with the PS lie flat seat. It just felt like a good solid 5 hours of uninterrupted sleep without the usual tossing and turning because of the warm temperatures in the cabin.