Scaffolding - amazing things, they turned the construction over forever. And you know what? They can FLY, such as stone, or quartz ore. It is enough only to build a tower to the border of 255 blocks, make a branch, click on any platform and ... VOILA! The block you click on will disappear, but a new one will appear in the direction of your look! And it does not fall, does not collapse! How do you like that?😉
i think that bug has been reported already and that block is a ghost block. if you relog it will disapear.