Dead horse my ass! There is a design issue with the cooling system and it isn't the head design. I speak from a little bit of personal experience here with now 4 different heads and two different FiSTs. 2014 with "old" head overheat. Warp. Coolant in cylinder 3. Replace engine after a year of complaining about overheats and replacement of almost every part on the cooling system. Ford doesn't want to cover the cost. Through some escalations it is covered after a deductible. New engine post 16 build date continues to overheat and car is liquidated for another "late" build 16 FiST. Begins to overheat at 20k and then it's winter here in MI. So 7 months later once temps get over 90 it begins the overheat cycle. Coolant in #3 again. New head gasket, head (assume it's the new one now as this was just this week), cams busted and valves bent. Just picked up car 1 hour ago, new head and all and 4 miles up the road, one small second gear pull and car starts to overheat. Then limp mode. It's back at dealer now. Temp was 87.
This horse ain't dead yet. I'm thinking those of you with coolant loss will suffer the same date eventually. Some may never know the issue in their engine I suspect. I recorded typical running temps over 225 in winter and once ambient temperature raises above 87 car cannot recover. Another interesting thing is that the Intake Air Temps I was recording in both cars was150-160 degrees when overheat occurred. Coolant temp got as high as 250. Ambient air had to be over 87 to cause situation and heat soak.
Make sure dealer is doing the coolant pressure test over time. There is a "new" procedure for this as of around July 2016. They will keep the car overnight for this test. This procedure was NOT in the manuals for the techs until this time and that is how mine was never diagnosed because a simple pressure test was always good.
Btw- no coolant loss is acceptable.