Dupes acting as thought they aren't wearing an exosuit

sounds like there's a priority related problem - I would set everything beyond the checkpoint as a higher priority than the usual 5. Kind of hard to remember doing this, but if you have enough dupes to run everything just fine in the base, then a small number working outside on higher priority shouldn't interfere with critical tasks. It could all be made a 9 and you're really only delegating as many dupes to the task as there are exosuits.

I haven't had them act differently because of heat while wearing exosuits, but it bothers me that they still complain about heat in 100° environments while wearing their suits (I know it doesn't affect them in any way, but it breaks the immersion a little bit).

Edited September 27, 2017 by Michi01

I actually set the priority of all dig and build tasks beyond the checkpoint to 9, and dupes were still just hopping in, digging 1 or 2 patches at a time, then dashing out. To get any work done in the oil biome, I have to set door to one-way only, and let them there overnight.