Not sure if this has been noted in another topic or if I am the only person that likes to do this, but I like to put a wall with a double door in front of my mine entrance just for the look of things. The trouble is that since I am building the wall a bit higher than the cave entrance I run into a little problem half the time. If the workers build the scaffolding outside the mine then I am good. If they build the scaffolding inside the mine, they have no actual room to stand on the scaffold to work and I start a long and frustrating ritual of making and deleting ladders to make my own scaffolds outside.
Recreating this is as simple as digging a hole facing the right direction and making a wall in front of it. If the scaffold pops inside the cave you can see the trouble easily.