Tahm Kench can't eat friendly pulsefire ezreal(gameplay)

I am referring to tahm Kench's devour ability (w). I was playing a tahm kench support game with a friendly ezreal vs caitlin Soraka on the other team. The game started normally, and I didn't notice anything wrong until one weird trade. I ate ezreal out of several sticky situaitons, but after 16 minutes, I could no longer eat him. Whenever i would press w with my cursor over ezreal, tahm would just stop his pathing and do nothing. I was still able to eat the rest of my team, but not ezreal. This continued for the remainder of the game.

I do not know how to reproduce this situation. This is the only time I have experienced this bug. I have played tahm kench with ezreal before and had no issues. Attached is a VOD of the game where I was 0/3/0 on tahm kench. (impressive score, i know) This is the game where I noticed the gameplay issue. The issue occured from approximately 16:15 to the end of the game.