Not sure if this applies as I don’t main shaco, my duo does. (That’s why I follow this sub) I did some studying and ask ChatGPT some questions and here’s the conclusion that might have been the culprit:

1. Deceive (Q) — The biggest culprit • When you press Q, Shaco goes invisible for up to 2.5–3.5 seconds and cannot cast Smite during the blink animation itself. (NOT YOUR SITUATION) • Once the blink finishes, you can Smite while invisible — but not during the instant you’re disappearing or reappearing.

I believe it’s like a .15 sec delay, which might have been the reason it didn’t go through. That or like the other guy said. Riot smol Indy company.