Pantheon Spear Shot Q Cancels Out Of Vision

In my past games with playing Pantheon, the opponent I chased had a spear shot following him but as soon as he gets out of vision or gets into a bush the spear does not follow up and just disappears and the enemy champion does not receive any damage. I suppose this is a bug issue that hasn't been fixed for years; there are a number of posts about it. The animation simply has no meaning while its following to take effect on the opponent that's targeted, but the effect never happens in out-of-vision situations. This does not make sense because Pantheon's spear just disappears as if from thin air and disintegrates. I conclude, by saying that, from my games that his spear shots work only when his opponents are visible for the full duration of Pantheon's Spear Shot animation, but this can be extremely frustrating for Pantheon players in ranked game when fighting in and out of the many bushes in Summoner's Rift 5V5.