Everything is in the title. I have tried to make tunnel for my compacts machines, but when I started the recipe by throwing a redstone, the blocks vanished and nothing happened. Also, an invisible block appeared, unbreakable.
This recipe works perfectly on singleplayer, that's why I think it's a server bug. I really need those tunnels because compacts machines are for the moment my only way to transport fluids across dimensions, there are others options but they are available only much later in the modpack.
I don't know if the staff can fix this bug. If it's not possible, it would be nice to add an other way to get tunnels (Sell it in the market, new crafting recipe...) because this makes compact machines totally useless.