When you place scaffolding in a certain manner, the scaffolding will glitch causing one part to fly in the air. If you place another scaffolding above or next to the part of the scaffolding that is glitched, the glitched part will disappear causing the part that has been placed above or next to the disappeared scaffolding to also glitch. And that will happen over and over again until the visible flying scaffolding has been destroyed by the player. I first discovered this glitch in 1.15 Pre-release 1. I hope that this issue can get fixed before the release of 1.15.