Hello,
since there was an update due to clipping base building has become much more difficult. Prior to this fencekits could be placed very close together to receive a higher amount of walls to get more protection done. Now if there are corner posts placed and another fencekit as close as possible, even without clipping the corner posts, it will also despawn a wall because there is minimal clipping in between the frame and the wall. In my honest opinion this checking method should be removed or the hitbox of the fencekit needs to have the correct hitbox to prevent a clipping failure and walls to despawn.
Greetings