I actually am not sure if tower bug is an actual "bug" or not. Could they really have unintentionally programmed the behavior of a tower to change once there's another tower in range? It seems like a bug because it's weird (one tower shooting further than the other) but it also follows the regular War2 behavior of units finishing or popping out at the top left.
It's totally how blizzard wanted to made it because it's more harder and more stategic.
They even explain how tower work on official war2 website...
They dont talk about bug, they talk about tower tactic, tower bug is only what peoples said to understand about what they talk, but there absolutly no bug.