Hi, I was looking at FrancisJohn’s video on geothermal power (https://www.youtube.com/watch?v=kyoLDP2tUaI), and tried the trick for building a “spike” deep down into lava (shown off at around 4:30 mark in the video).

However, my dupes do not seem able to build through the closed horizontal airlock. Has this trick been patched out?