The problem with those strips is it also measures the environmental temp if they aren't sealed and seated 100%. Its almost like it takes an average reading of the ambient tempreture as well as the vessel. I've seen my temp strip read -6% from a laser reader before...and that could make all the difference
For what it's worth, i'm a bucket guy. The water circulating around my RISs and DIPAs is set to 60f for day 2-3. Day 1 and 4, about 63-65. I've ran into other off flavor issues, but never the fermented to high temp flavor..which I'm aware of myself.