Funny side of bugs

This is the funniest bug I have yet found in my game. My first base. Only some of the walls get build and suddenly after I clicked on a wall this message comes up and my builders charge in, I am delighted as it looks like they are going to finish it at last… not so fast though as they don’t build the floor (yes I am sure I placed a floor) … they dig it up !! lol.

What is the strangest thing to happen to you while building ?

Sorry everybody… this is no bug just me new to building my own thing. The building had errors so I thought this was one too.