This sorat thing happened to me as well.I was building some piston sandgate for a sorta secret base.The redstone was placed on very small room so it was pretty complicated.When I first tested it with a button it worked but as soon as I used a lever,every redstone in that circuit dropped...
Seems to be a bug when a specific redstone circuit that includes repeater a lever and a piston breaks all redstone stuff.All that happens is: The redstone gets bugged and due to the change of state of the blocks Minecraft analyses that as wrong and simply breaks the block.That happens with buggy water, floating torches and single portal blocks as well.