Oathsworn is not showing up on Kalista [GAMEPLAY]

I was playing a normal game as Kalista and I tried to use my black spear to make my support my oathsworn. My first attempt did not work, it made the noise as if it were but the passive icon did not pop up. I then bought a new black spear because the other was gone from my inventory again, this time it worked but the black spear stayed in my inventory and the marker around the champions did not appear nor did the animation carry out to its full extent. I know it doesn't affect much gameplay wise but it does cause some confusion and anger in the game having to go back to get another spear. Also if it helps my support was Alistar.