You have had some strange hatches for sure.
It makes no sense. I use all 1202's incubators and hatchers, I have them in a 70 degree room. I have the auto humidity thing (bucket on the cabinet)..
I get good hatches unless the eggs freeze or get too cold. But the heat wrap shrinking has always been a pain, one or two eggs out of 100 do it. I run 45% humidity during incubation I run 65-75% during the hatch.
I run a little higher than most because of the heat shrinking.
I am in the process of building a new hatchery. I need it because the USDA vet says I do,,,sigh....