Seeing Caitlyn becoming too powerful, Riot Games decided to completely remove the damage from her Q ability in order to balance her out.

It's noteworthy here that this bug isn't just affecting champions but even when used on minions, jungle monsters, the damage from Q - Piltover Peacemaker completely disappears. Remember that Marksmen have very few defensive items to protect themselves, and Shadow Cloak is one of them. With the aforementioned bug, the number of defensive items Caitlyn can buy becomes even fewer because no one wants their skill to be 'useless'.

Besides, this isn't the first time this bug has occurred in LoL. According to the 'bug guru' Vandiril, Sona and her ultimate Crescendo also faced a similar issue when it didn't deal any damage or stun if the champion owned Crucible, Thornmail. This bug has been happening for 6 months before Sona was lightly reworked and it has resurfaced with the latest victim named Caitlyn.

Riot Games probably needs to conduct a thorough review of its champions when abilities like Caitlyn's and Sona's are so popular. Hopefully, Riot will find the quickest possible way to fix this bug without causing too much disruption to the game.