My Core Set finally arrived today. I've had just enough time to skim through it and sleeve all the cards, but when doing so, I've noticed there are only two copies of the Melee Strike card, whereas other basic actions are there in 3 copies.

Am I missing a card, or is it supposed to be that way?

I do believe you're missing a card. I have three in my set.

Thanks. I'll sort that out with my FLGS.