A few creations I have made don't work with repeater inputs, such as a 5x5 piston door, and a 5x5 skydoor. However, the doors worked just fine when just a lever is used. Other inputs such as redstone torches, pistons with redstone blocks, and comparators didn't work either. I built a small contraption to demonstrate the issue, where depending on whether you flip the lever with the repeater, or no repeater, the piston will pulse once, or twice. The hopper has ONE item inside.