As I was crafting "compact machine wall" the item preview did not disappear any more after the item was already dropped. I tried disabling all the projectors using a redstone signal. I tried breaking the projectors and putting them back. I tried moving the projector up 3 block to no longer have the block be contained inside the area, but this just resulted in the same issue. I tried putting a piston below the block to attempt to push the block away. I also tried to build around the block and break the surrounding blocks using a hammer. After trying all this I disconnected and reconnected. Which showed me that the preview had disappeared, but was still on the server and now the following error is shown when right clicking on one of the projectors: "Invalid block in field area @ -1271, 23, 2521: Air" I still have the piston with a lever below it. To check if the Air block is still there and when flipping the lever the piston does nothing. My hope was that it might have been fixed after the restart, but no luck. I looked around for existing reports of this problem, but could not find anything. Are there any known issues with Compact machines ? Are there any known work arounds ?