Maybe it is just because I left some oxylite in space so the dupe could breath but I still don't know why the CO2 they exhale should reach a closed space and not be deleted by vacuum
The exhale "bubble" is visible and heading down, before appearing in the two tiles of steam.
It can happen consistently in this save CO2 tele 3.sav
It only appears when there are other gases in the enclosed area. It can happen when a dupe uses oxygen mask. tele breath 2_.sav
Visible exhale bubbles forming 20g CO2 underneath
Let dupes exhale in space either using sandbox or oxygen masks