Big cat, small cat. Size reference would be nice, but the small is very very small relative to the large track. I've seen lots of times where Cougars and Bobcats cross paths, even follow each other's tracks for a ways (both following both at different times.) Could be that. Could be a cub, but that's a young cub. Did you follow? Did they both line out and stay together, or did they go separate ways?