[Gameplay] Spellthief's Edge not proccing in early game

I've had a few games recently where I'd be waiting to see if someone goes into that one square of bush in bottom river (usually to ward but sometimes to set up an invade) and I manage to hit them with a Q, some auto attacks, my Q again... but the Spellthief's Edge would neither do extra damage nor give me gold. It would remain at 3 charges and I'd get nothing from it at all. Usually, if someone shows up and I hit them, I get some gold from it (33-55 depending on how invested they are in the tit for tat) and can at least get the Faerie Charm.

After roughly 2 minutes, it seems to work without problems.

In my experience (and as far as I remember), it only happens when I'm on Red Team, but it doesn't always happen.

For the record, I'm virtually a one-trick Soraka, but this last game was as Lux, and it's happened when I play Zilean as well. It's also always Ranked Solo/Duo, but I don't play much else so IDK how relevant that information is.

Thanks