[GAMEPLAY] Thresh hook not working on Sion passive

I just played an ARAM as Thresh and noticed my q wouldn't work on Sion once he had died and was in his passive.

1. Sion respawns in his passive
2. I throw q and it hits
3. The chain immediately disappears and sion is unaffected, but I get the 3 second cd from hitting an enemy with it.

This happened every time i tried to hook him. Flay worked fine though.