[GAMEPLAY] Kalista Rend sound effect playing on-hit

Played a game as Kalista today on Patch 7.2 live server.

About 22 minutes into the game, basic attacking a target caused the Rend sound effect to play, without Rend being cast.

Basic attacking the target caused the sound effect to play. Everything else continued as normal. Continued basic attacks (increasing Rend stacks, on same or different target) did not trigger the sound effect again. After casting E - Rend, the next basic attack would again trigger the sound effect.

This glitch repeated itself for roughly two minutes, after which I backed and the glitch did not repeat again.

I am unsure of how to replicate this glitch.