Sometimes I'd curl my toes up when I'm making an effort without realizing it and I was also velcro-ing the strap over the ball of my foot too tight. I've relaxed both of those things and now no more numbness for me.

I've never had to wear in bike shoes, nor have had any shoes that cause discomfort ever changed their ways. Would you be able to try out others, possibly return these if they are the culprit?