bleeding after light work out??

I've worked out some after my pregnancy. Mostly just a barre class 1-2 times a week. We recently had our schools jog-a-thin and I did a brisk walk/ light jog (kids were walking faster than me, so it wasn't anything crazy). I started bleeding shortly after and only for that day. My period hasn't returned as I'm ebf. Has anyone else had this issue? Bleeding after working out? I haven't had any bleeding after sex...