2001 Isuzu Rodeo Spark Plug Boots



I recently replaced the spark plugs on my Isuzu DHOC V6 and discovered that the number 6 cylinder has a different coil boot than the other five. It is slightly shorter and has a notch in the top corresponding with a tab on the coil, though all the coils appear to be the same. Can anyone tell me why one cylinder would be different from all the rest?