As this bug is quite complicated, I will talk about how to recreate it first. Place two redstone dust, then a block in front of the redstone, and a piston in front of the block. Place a piston next to the redstone dust which is next to the block. Power the redstone line at the redstone at the back, both pistons get powered. This is because pistons do NOT redirect redstone, but the texture shows that it does redirect redstone and power the piston at the same time.